The orderly segregation of CHROMOSOMES during MEIOSIS or MITOSIS.
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Large multiprotein complexes that bind the centromeres of the chromosomes to the microtubules of the mitotic spindle during metaphase in the cell cycle.
Any method used for determining the location of and relative distances between genes on a chromosome.
A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species.
A microtubule structure that forms during CELL DIVISION. It consists of two SPINDLE POLES, and sets of MICROTUBULES that may include the astral microtubules, the polar microtubules, and the kinetochore microtubules.
The clear constricted portion of the chromosome at which the chromatids are joined and by which the chromosome is attached to the spindle during cell division.
Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell.
A type of CELL NUCLEUS division, occurring during maturation of the GERM CELLS. Two successive cell nucleus divisions following a single chromosome duplication (S PHASE) result in daughter cells with half the number of CHROMOSOMES as the parent cells.
Nucleoproteins, which in contrast to HISTONES, are acid insoluble. They are involved in chromosomal functions; e.g. they bind selectively to DNA, stimulate transcription resulting in tissue-specific RNA synthesis and undergo specific changes in response to various hormones or phytomitogens.
Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.
The female sex chromosome, being the differential sex chromosome carried by half the male gametes and all female gametes in human and other male-heterogametic species.
A family of highly conserved serine-threonine kinases that are involved in the regulation of MITOSIS. They are involved in many aspects of cell division, including centrosome duplication, SPINDLE APPARATUS formation, chromosome alignment, attachment to the spindle, checkpoint activation, and CYTOKINESIS.
Proteins that control the CELL DIVISION CYCLE. This family of proteins includes a wide variety of classes, including CYCLIN-DEPENDENT KINASES, mitogen-activated kinases, CYCLINS, and PHOSPHOPROTEIN PHOSPHATASES as well as their putative substrates such as chromatin-associated proteins, CYTOSKELETAL PROTEINS, and TRANSCRIPTION FACTORS.
The phase of cell nucleus division following METAPHASE, in which the CHROMATIDS separate and migrate to opposite poles of the spindle.
Staining of bands, or chromosome segments, allowing the precise identification of individual chromosomes or parts of chromosomes. Applications include the determination of chromosome rearrangements in malformation syndromes and cancer, the chemistry of chromosome segments, chromosome changes during evolution, and, in conjunction with cell hybridization studies, chromosome mapping.
The alignment of CHROMOSOMES at homologous sequences.
Either of the two longitudinally adjacent threads formed when a eukaryotic chromosome replicates prior to mitosis. The chromatids are held together at the centromere. Sister chromatids are derived from the same chromosome. (Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.
Very long DNA molecules and associated proteins, HISTONES, and non-histone chromosomal proteins (CHROMOSOMAL PROTEINS, NON-HISTONE). Normally 46 chromosomes, including two sex chromosomes are found in the nucleus of human cells. They carry the hereditary information of the individual.
The homologous chromosomes that are dissimilar in the heterogametic sex. There are the X CHROMOSOME, the Y CHROMOSOME, and the W, Z chromosomes (in animals in which the female is the heterogametic sex (the silkworm moth Bombyx mori, for example)). In such cases the W chromosome is the female-determining and the male is ZZ. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
The phase of cell nucleus division following PROMETAPHASE, in which the CHROMOSOMES line up across the equatorial plane of the SPINDLE APPARATUS prior to separation.
Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.
A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.
An aurora kinase that is a component of the chromosomal passenger protein complex and is involved in the regulation of MITOSIS. It mediates proper CHROMOSOME SEGREGATION and contractile ring function during CYTOKINESIS.
The chromosomal constitution of cells which deviate from the normal by the addition or subtraction of CHROMOSOMES, chromosome pairs, or chromosome fragments. In a normally diploid cell (DIPLOIDY) the loss of a chromosome pair is termed nullisomy (symbol: 2N-2), the loss of a single chromosome is MONOSOMY (symbol: 2N-1), the addition of a chromosome pair is tetrasomy (symbol: 2N+2), the addition of a single chromosome is TRISOMY (symbol: 2N+1).
The failure of homologous CHROMOSOMES or CHROMATIDS to segregate during MITOSIS or MEIOSIS with the result that one daughter cell has both of a pair of parental chromosomes or chromatids and the other has none.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A genus of ascomycetous fungi of the family Schizosaccharomycetaceae, order Schizosaccharomycetales.
Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of PLANTS.
Proteins obtained from the species Schizosaccharomyces pombe. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.
Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
Actual loss of portion of a chromosome.
A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.
A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.
Mad2 is a component of the spindle-assembly checkpoint apparatus. It binds to and inhibits the Cdc20 activator subunit of the anaphase-promoting complex, preventing the onset of anaphase until all chromosomes are properly aligned at the metaphase plate. Mad2 is required for proper microtubule capture at KINETOCHORES.
Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of MAMMALS.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A specific pair GROUP C CHROMSOMES of the human chromosome classification.
A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.
A specific pair of GROUP C CHROMSOMES of the human chromosome classification.
A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei.
Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.
The cellular signaling system that halts the progression of cells through MITOSIS or MEIOSIS if a defect that will affect CHROMOSOME SEGREGATION is detected.
Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.
The medium-sized, submetacentric human chromosomes, called group C in the human chromosome classification. This group consists of chromosome pairs 6, 7, 8, 9, 10, 11, and 12 and the X chromosome.
A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.
An increased tendency to acquire CHROMOSOME ABERRATIONS when various processes involved in chromosome replication, repair, or segregation are dysfunctional.
The cell center, consisting of a pair of CENTRIOLES surrounded by a cloud of amorphous material called the pericentriolar region. During interphase, the centrosome nucleates microtubule outgrowth. The centrosome duplicates and, during mitosis, separates to form the two poles of the mitotic spindle (MITOTIC SPINDLE APPARATUS).
Separase is a caspase-like cysteine protease, which plays a central role in triggering ANAPHASE by cleaving the SCC1/RAD21 subunit of the cohesin complex. Cohesin holds the sister CHROMATIDS together during METAPHASE and its cleavage results in chromosome segregation.
High molecular weight proteins found in the MICROTUBULES of the cytoskeletal system. Under certain conditions they are required for TUBULIN assembly into the microtubules and stabilize the assembled microtubules.
A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.
A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.
A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.
The process by which the CYTOPLASM of a cell is divided.
A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.
Mapping of the KARYOTYPE of a cell.
The mechanisms of eukaryotic CELLS that place or keep the CHROMOSOMES in a particular SUBNUCLEAR SPACE.
A microtubule-associated mechanical adenosine triphosphatase, that uses the energy of ATP hydrolysis to move organelles along microtubules toward the plus end of the microtubule. The protein is found in squid axoplasm, optic lobes, and in bovine brain. Bovine kinesin is a heterotetramer composed of two heavy (120 kDa) and two light (62 kDa) chains. EC 3.6.1.-.
A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.
A specific pair of GROUP B CHROMOSOMES of the human chromosome classification.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
The human male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans.
The co-inheritance of two or more non-allelic GENES due to their being located more or less closely on the same CHROMOSOME.
Structures which are contained in or part of CHROMOSOMES.
A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.
A specific pair of GROUP F CHROMOSOMES of the human chromosome classification.
Clinical conditions caused by an abnormal chromosome constitution in which there is extra or missing chromosome material (either a whole chromosome or a chromosome segment). (from Thompson et al., Genetics in Medicine, 5th ed, p429)
The first phase of cell nucleus division, in which the CHROMOSOMES become visible, the CELL NUCLEUS starts to lose its identity, the SPINDLE APPARATUS appears, and the CENTRIOLES migrate toward opposite poles.
The human female sex chromosome, being the differential sex chromosome carried by half the male gametes and all female gametes in humans.
The large, metacentric human chromosomes, called group A in the human chromosome classification. This group consists of chromosome pairs 1, 2, and 3.
DNA constructs that are composed of, at least, a REPLICATION ORIGIN, for successful replication, propagation to and maintenance as an extra chromosome in bacteria. In addition, they can carry large amounts (about 200 kilobases) of other sequence for a variety of bioengineering purposes.
A technique for visualizing CHROMOSOME ABERRATIONS using fluorescently labeled DNA probes which are hybridized to chromosomal DNA. Multiple fluorochromes may be attached to the probes. Upon hybridization, this produces a multicolored, or painted, effect with a unique color at each site of hybridization. This technique may also be used to identify cross-species homology by labeling probes from one species for hybridization with chromosomes from another species.
One of the two pairs of human chromosomes in the group B class (CHROMOSOMES, HUMAN, 4-5).
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.
A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.
Proteins found in any species of fungus.
A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.
The phase of cell nucleus division following PROPHASE, when the breakdown of the NUCLEAR ENVELOPE occurs and the MITOTIC SPINDLE APPARATUS enters the nuclear region and attaches to the KINETOCHORES.
The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.
A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
Macromolecular complexes formed from the association of defined protein subunits.
The medium-sized, acrocentric human chromosomes, called group D in the human chromosome classification. This group consists of chromosome pairs 13, 14, and 15.
A specific pair of GROUP F CHROMOSOMES of the human chromosome classification.
Chromosomes in which fragments of exogenous DNA ranging in length up to several hundred kilobase pairs have been cloned into yeast through ligation to vector sequences. These artificial chromosomes are used extensively in molecular biology for the construction of comprehensive genomic libraries of higher organisms.
Structures within the CELL NUCLEUS of insect cells containing DNA.
The short, submetacentric human chromosomes, called group E in the human chromosome classification. This group consists of chromosome pairs 16, 17, and 18.
An exchange of segments between the sister chromatids of a chromosome, either between the sister chromatids of a meiotic tetrad or between the sister chromatids of a duplicated somatic chromosome. Its frequency is increased by ultraviolet and ionizing radiation and other mutagenic agents and is particularly high in BLOOM SYNDROME.
The process by which a DNA molecule is duplicated.
Deliberate breeding of two different individuals that results in offspring that carry part of the genetic material of each parent. The parent organisms must be genetically compatible and may be from different varieties or closely related species.
Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.
The material of CHROMOSOMES. It is a complex of DNA; HISTONES; and nonhistone proteins (CHROMOSOMAL PROTEINS, NON-HISTONE) found within the nucleus of a cell.
Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.
Small chromosomal proteins (approx 12-20 kD) possessing an open, unfolded structure and attached to the DNA in cell nuclei by ionic linkages. Classification into the various types (designated histone I, histone II, etc.) is based on the relative amounts of arginine and lysine in each.
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
The short, acrocentric human chromosomes, called group G in the human chromosome classification. This group consists of chromosome pairs 21 and 22 and the Y chromosome.
An aberration in which a chromosomal segment is deleted and reinserted in the same place but turned 180 degrees from its original orientation, so that the gene sequence for the segment is reversed with respect to that of the rest of the chromosome.
A type of chromosome aberration characterized by CHROMOSOME BREAKAGE and transfer of the broken-off portion to another location, often to a different chromosome.
Deoxyribonucleic acid that makes up the genetic material of fungi.
The process by which the CELL NUCLEUS is divided.
The prophase of the first division of MEIOSIS (in which homologous CHROMOSOME SEGREGATION occurs). It is divided into five stages: leptonema, zygonema, PACHYNEMA, diplonema, and diakinesis.
A gene silencing phenomenon whereby specific dsRNAs (RNA, DOUBLE-STRANDED) trigger the degradation of homologous mRNA (RNA, MESSENGER). The specific dsRNAs are processed into SMALL INTERFERING RNA (siRNA) which serves as a guide for cleavage of the homologous mRNA in the RNA-INDUCED SILENCING COMPLEX. DNA METHYLATION may also be triggered during this process.
The functional hereditary units of FUNGI.
The reciprocal exchange of segments at corresponding positions along pairs of homologous CHROMOSOMES by symmetrical breakage and crosswise rejoining forming cross-over sites (HOLLIDAY JUNCTIONS) that are resolved during CHROMOSOME SEGREGATION. Crossing-over typically occurs during MEIOSIS but it may also occur in the absence of meiosis, for example, with bacterial chromosomes, organelle chromosomes, or somatic cell nuclear chromosomes.
A species of fruit fly much used in genetics because of the large size of its chromosomes.
Aberrant chromosomes with no ends, i.e., circular.
Securin is involved in the control of the metaphase-anaphase transition during MITOSIS. It promotes the onset of anaphase by blocking SEPARASE function and preventing proteolysis of cohesin and separation of sister CHROMATIDS. Overexpression of securin is associated with NEOPLASTIC CELL TRANSFORMATION and tumor formation.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
The large, submetacentric human chromosomes, called group B in the human chromosome classification. This group consists of chromosome pairs 4 and 5.
A species of nematode that is widely used in biological, biochemical, and genetic studies.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.
Male germ cells derived from SPERMATOGONIA. The euploid primary spermatocytes undergo MEIOSIS and give rise to the haploid secondary spermatocytes which in turn give rise to SPERMATIDS.
Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Any cell, other than a ZYGOTE, that contains elements (such as NUCLEI and CYTOPLASM) from two or more different cells, usually produced by artificial CELL FUSION.
The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.
The chromosomal constitution of a cell containing multiples of the normal number of CHROMOSOMES; includes triploidy (symbol: 3N), tetraploidy (symbol: 4N), etc.
The record of descent or ancestry, particularly of a particular condition or trait, indicating individual family members, their relationships, and their status with respect to the trait or condition.
The three-part structure of ribbon-like proteinaceous material that serves to align and join the paired homologous CHROMOSOMES. It is formed during the ZYGOTENE STAGE of the first meiotic division. It is a prerequisite for CROSSING OVER.
Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.
DNA TOPOISOMERASES that catalyze ATP-dependent breakage of both strands of DNA, passage of the unbroken strands through the breaks, and rejoining of the broken strands. These enzymes bring about relaxation of the supercoiled DNA and resolution of a knotted circular DNA duplex.
Highly conserved proteins that specifically bind to and activate the anaphase-promoting complex-cyclosome, promoting ubiquitination and proteolysis of cell-cycle-regulatory proteins. Cdc20 is essential for anaphase-promoting complex activity, initiation of anaphase, and cyclin proteolysis during mitosis.
A terminal section of a chromosome which has a specialized structure and which is involved in chromosomal replication and stability. Its length is believed to be a few hundred base pairs.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Proteins from the nematode species CAENORHABDITIS ELEGANS. The proteins from this species are the subject of scientific interest in the area of multicellular organism MORPHOGENESIS.
An increased tendency of the GENOME to acquire MUTATIONS when various processes involved in maintaining and replicating the genome are dysfunctional.
Complexes of enzymes that catalyze the covalent attachment of UBIQUITIN to other proteins by forming a peptide bond between the C-terminal GLYCINE of UBIQUITIN and the alpha-amino groups of LYSINE residues in the protein. The complexes play an important role in mediating the selective-degradation of short-lived and abnormal proteins. The complex of enzymes can be broken down into three components that involve activation of ubiquitin (UBIQUITIN-ACTIVATING ENZYMES), conjugation of ubiquitin to the ligase complex (UBIQUITIN-CONJUGATING ENZYMES), and ligation of ubiquitin to the substrate protein (UBIQUITIN-PROTEIN LIGASES).
Nocodazole is an antineoplastic agent which exerts its effect by depolymerizing microtubules.
A family of rat kangaroos found in and around Australia. Genera include Potorous and Bettongia.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
The degree of replication of the chromosome set in the karyotype.
Genes whose loss of function or gain of function MUTATION leads to the death of the carrier prior to maturity. They may be essential genes (GENES, ESSENTIAL) required for viability, or genes which cause a block of function of an essential gene at a time when the essential gene function is required for viability.
2-Substituted benzimidazole first introduced in 1962. It is active against a variety of nematodes and is the drug of choice for STRONGYLOIDIASIS. It has CENTRAL NERVOUS SYSTEM side effects and hepatototoxic potential. (From Smith and Reynard, Textbook of Pharmacology, 1992, p919)
An order of fungi in the phylum Ascomycota that multiply by budding. They include the telomorphic ascomycetous yeasts which are found in a very wide range of habitats.
A microtubule subunit protein found in large quantities in mammalian brain. It has also been isolated from SPERM FLAGELLUM; CILIA; and other sources. Structurally, the protein is a dimer with a molecular weight of approximately 120,000 and a sedimentation coefficient of 5.8S. It binds to COLCHICINE; VINCRISTINE; and VINBLASTINE.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
A dosage compensation process occurring at an early embryonic stage in mammalian development whereby, at random, one X CHROMOSOME of the pair is repressed in the somatic cells of females.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.
An E3 ubiquitin ligase primarily involved in regulation of the metaphase-to-anaphase transition during MITOSIS through ubiquitination of specific CELL CYCLE PROTEINS. Enzyme activity is tightly regulated through subunits and cofactors, which modulate activation, inhibition, and substrate specificity. The anaphase-promoting complex, or APC-C, is also involved in tissue differentiation in the PLACENTA, CRYSTALLINE LENS, and SKELETAL MUSCLE, and in regulation of postmitotic NEURONAL PLASTICITY and excitability.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
CIRCULAR DNA that is interlaced together as links in a chain. It is used as an assay for the activity of DNA TOPOISOMERASES. Catenated DNA is attached loop to loop in contrast to CONCATENATED DNA which is attached end to end.
An aurora kinase that localizes to the CENTROSOME during MITOSIS and is involved in centrosome regulation and formation of the MITOTIC SPINDLE. Aurora A overexpression in many malignant tumor types suggests that it may be directly involved in NEOPLASTIC CELL TRANSFORMATION.
The portion of chromosome material that remains condensed and is transcriptionally inactive during INTERPHASE.
Reproductive bodies produced by fungi.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
A genus of gram-negative, aerobic, rod- or vibroid-shaped or fusiform bacteria that commonly produce a stalk. They are found in fresh water and soil and divide by binary transverse fission.
The short, metacentric human chromosomes, called group F in the human chromosome classification. This group consists of chromosome pairs 19 and 20.
A unique DNA sequence of a replicon at which DNA REPLICATION is initiated and proceeds bidirectionally or unidirectionally. It contains the sites where the first separation of the complementary strands occurs, a primer RNA is synthesized, and the switch from primer RNA to DNA synthesis takes place. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
The interval between two successive CELL DIVISIONS during which the CHROMOSOMES are not individually distinguishable. It is composed of the G phases (G1 PHASE; G0 PHASE; G2 PHASE) and S PHASE (when DNA replication occurs).
Genes that code for proteins that regulate the CELL DIVISION CYCLE. These genes form a regulatory network that culminates in the onset of MITOSIS by activating the p34cdc2 protein (PROTEIN P34CDC2).
Proteins found in any species of bacterium.
The chromosomal constitution of cells, in which each type of CHROMOSOME is represented twice. Symbol: 2N or 2X.
The stage in the first meiotic prophase, following ZYGOTENE STAGE, when CROSSING OVER between homologous CHROMOSOMES begins.
Aurora kinase C is a chromosomal passenger protein that interacts with aurora kinase B in the regulation of MITOSIS. It is found primarily in GERM CELLS in the TESTIS, and may mediate CHROMOSOME SEGREGATION during SPERMATOGENESIS.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Interruptions in the sugar-phosphate backbone of DNA, across both strands adjacently.
An individual having different alleles at one or more loci regarding a specific character.
A variety of simple repeat sequences that are distributed throughout the GENOME. They are characterized by a short repeat unit of 2-8 basepairs that is repeated up to 100 times. They are also known as short tandem repeats (STRs).
The total relative probability, expressed on a logarithmic scale, that a linkage relationship exists among selected loci. Lod is an acronym for "logarithmic odds."
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
An amorphous region of electron dense material in the cytoplasm from which the MICROTUBULES polymerization is nucleated. The pericentriolar region of the CENTROSOME which surrounds the CENTRIOLES is an example.
A family of multisubunit cytoskeletal motor proteins that use the energy of ATP hydrolysis to power a variety of cellular functions. Dyneins fall into two major classes based upon structural and functional criteria.
Minute cells produced during development of an OOCYTE as it undergoes MEIOSIS. A polar body contains one of the nuclei derived from the first or second meiotic CELL DIVISION. Polar bodies have practically no CYTOPLASM. They are eventually discarded by the oocyte. (from King & Stansfield, A Dictionary of Genetics, 4th ed)
A DNA-binding protein that interacts with a 17-base pair sequence known as the CENP-B box motif. The protein is localized constitutively to the CENTROMERE and plays an important role in its maintenance.
Established cell cultures that have the potential to propagate indefinitely.
A species of gram-negative, aerobic bacteria that consist of slender vibroid cells.
Genes that influence the PHENOTYPE both in the homozygous and the heterozygous state.
The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.
Phosphoprotein with protein kinase activity that functions in the G2/M phase transition of the CELL CYCLE. It is the catalytic subunit of the MATURATION-PROMOTING FACTOR and complexes with both CYCLIN A and CYCLIN B in mammalian cells. The maximal activity of cyclin-dependent kinase 1 is achieved when it is fully dephosphorylated.
Highly repetitive DNA sequences found in HETEROCHROMATIN, mainly near centromeres. They are composed of simple sequences (very short) (see MINISATELLITE REPEATS) repeated in tandem many times to form large blocks of sequence. Additionally, following the accumulation of mutations, these blocks of repeats have been repeated in tandem themselves. The degree of repetition is on the order of 1000 to 10 million at each locus. Loci are few, usually one or two per chromosome. They were called satellites since in density gradients, they often sediment as distinct, satellite bands separate from the bulk of genomic DNA owing to a distinct BASE COMPOSITION.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in fungi.
The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein.
A plant genus of the family POACEAE originating from the savanna of eastern Africa. It is widely grown for livestock forage.
Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Proteins obtained from ESCHERICHIA COLI.
A cyclin subtype that is transported into the CELL NUCLEUS at the end of the G2 PHASE. It stimulates the G2/M phase transition by activating CDC2 PROTEIN KINASE.
The functional hereditary units of INSECTS.
A cross-shaped DNA structure that can be observed under the electron microscope. It is formed by the incomplete exchange of strands between two double-stranded helices or by complementary INVERTED REPEAT SEQUENCES that refold into hairpin loops on opposite strands across from each other.
Within most types of eukaryotic CELL NUCLEUS, a distinct region, not delimited by a membrane, in which some species of rRNA (RNA, RIBOSOMAL) are synthesized and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rRNA is transcribed from a nucleolar organizer, i.e., a group of tandemly repeated chromosomal genes which encode rRNA and which are transcribed by RNA polymerase I. (Singleton & Sainsbury, Dictionary of Microbiology & Molecular Biology, 2d ed)
The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.
Proteins that catalyze the unwinding of duplex DNA during replication by binding cooperatively to single-stranded regions of DNA or to short regions of duplex DNA that are undergoing transient opening. In addition DNA helicases are DNA-dependent ATPases that harness the free energy of ATP hydrolysis to translocate DNA strands.
Mutation process that restores the wild-type PHENOTYPE in an organism possessing a mutationally altered GENOTYPE. The second "suppressor" mutation may be on a different gene, on the same gene but located at a distance from the site of the primary mutation, or in extrachromosomal genes (EXTRACHROMOSOMAL INHERITANCE).
Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).
Abnormal increase in the interorbital distance due to overdevelopment of the lesser wings of the sphenoid.
A broad category of enzymes that are involved in the process of GENETIC RECOMBINATION.
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.

Mutations at phosphorylation sites of Xenopus microtubule-associated protein 4 affect its microtubule-binding ability and chromosome movement during mitosis. (1/2093)

Microtubule-associated proteins (MAPs) bind to and stabilize microtubules (MTs) both in vitro and in vivo and are thought to regulate MT dynamics during the cell cycle. It is known that p220, a major MAP of Xenopus, is phosphorylated by p34(cdc2) kinase as well as MAP kinase in mitotic cells, and that the phosphorylated p220 loses its MT-binding and -stabilizing abilities in vitro. We cloned a full-length cDNA encoding p220, which identified p220 as a Xenopus homologue of MAP4 (XMAP4). To examine the physiological relevance of XMAP4 phosphorylation in vivo, Xenopus A6 cells were transfected with cDNAs encoding wild-type or various XMAP4 mutants fused with a green fluorescent protein. Mutations of serine and threonine residues at p34(cdc2) kinase-specific phosphorylation sites to alanine interfered with mitosis-associated reduction in MT affinity of XMAP4, and their overexpression affected chromosome movement during anaphase A. These findings indicated that phosphorylation of XMAP4 (probably by p34(cdc2) kinase) is responsible for the decrease in its MT-binding and -stabilizing abilities during mitosis, which are important for chromosome movement during anaphase A.  (+info)

Gene knockouts reveal separate functions for two cytoplasmic dyneins in Tetrahymena thermophila. (2/2093)

In many organisms, there are multiple isoforms of cytoplasmic dynein heavy chains, and division of labor among the isoforms would provide a mechanism to regulate dynein function. The targeted disruption of somatic genes in Tetrahymena thermophila presents the opportunity to determine the contributions of individual dynein isoforms in a single cell that expresses multiple dynein heavy chain genes. Substantial portions of two Tetrahymena cytoplasmic dynein heavy chain genes were cloned, and their motor domains were sequenced. Tetrahymena DYH1 encodes the ubiquitous cytoplasmic dynein Dyh1, and DYH2 encodes a second cytoplasmic dynein isoform, Dyh2. The disruption of DYH1, but not DYH2, resulted in cells with two detectable defects: 1) phagocytic activity was inhibited, and 2) the cells failed to distribute their chromosomes correctly during micronuclear mitosis. In contrast, the disruption of DYH2 resulted in a loss of regulation of cell size and cell shape and in the apparent inability of the cells to repair their cortical cytoskeletons. We conclude that the two dyneins perform separate tasks in Tetrahymena.  (+info)

Regulation of Saccharomyces cerevisiae kinetochores by the type 1 phosphatase Glc7p. (3/2093)

We have investigated the role of protein phosphorylation in regulation of Saccharomyces cerevisiae kinetochores. By use of phosphatase inhibitors and a type 1 protein phosphatase mutant (glc7-10), we show that the microtubule binding activity, but not the centromeric DNA-binding activity, of the kinetochore complex is regulated by a balance between a protein kinase and the type 1 protein phosphatase (PP1) encoded by the GLC7 gene. glc7-10 mutant cells exhibit low kinetochore-microtubule binding activity in vitro and a high frequency of chromosome loss in vivo. Specifically, the Ndc10p component of the centromere DNA-binding CBF3 complex is altered by the glc7-10 mutation; Ndc10p is hyperphosphorylated in glc7-10 extracts. Furthermore, addition of recombinant Ndc10p reconstitutes the microtubule-binding activity of a glc7-10 extract to wild-type levels. Finally, the glc7-10-induced mitotic arrest is abolished in spindle checkpoint mutants, suggesting that defects in kinetochore-microtubule interactions caused by hyperphosphorylation of kinetochore proteins activate the spindle checkpoint.  (+info)

Genetic linkage of IgA deficiency to the major histocompatibility complex: evidence for allele segregation distortion, parent-of-origin penetrance differences, and the role of anti-IgA antibodies in disease predisposition. (4/2093)

Immunoglobulin A (IgA) deficiency (IgAD) is characterized by a defect of terminal lymphocyte differentiation, leading to a lack of IgA in serum and mucosal secretions. Familial clustering, variable population prevalence in different ethnic groups, and a predominant inheritance pattern suggest a strong genetic predisposition to IgAD. The genetic susceptibility to IgAD is shared with a less prevalent, but more profound, defect called "common variable immunodeficiency" (CVID). Here we show an increased allele sharing at 6p21 in affected members of 83 multiplex IgAD/CVID pedigrees and demonstrate, using transmission/diseqilibrium tests, family-based associations indicating the presence of a predisposing locus, designated "IGAD1," in the proximal part of the major histocompatibility complex (MHC). The recurrence risk of IgAD was found to depend on the sex of parents transmitting the defect: affected mothers were more likely to produce offspring with IgAD than were affected fathers. Carrier mothers but not carrier fathers transmitted IGAD1 alleles more frequently to the affected offspring than would be expected under random segregation. The differential parent-of-origin penetrance is proposed to reflect a maternal effect mediated by the production of anti-IgA antibodies tentatively linked to IGAD1. This is supported by higher frequency of anti-IgA-positive females transmitting the disorder to children, in comparison with female IgAD nontransmitters, and by linkage data in the former group. Such pathogenic mechanisms may be shared by other MHC-linked complex traits associated with the production of specific autoantibodies, parental effects, and a particular MHC haplotype.  (+info)

Comparisons of genomic structures and chromosomal locations of the mouse aldose reductase and aldose reductase-like genes. (5/2093)

Aldose reductase (AR), best known as the first enzyme in the polyol pathway of sugar metabolism, has been implicated in a wide variety of physiological functions and in the etiology of diabetic complications. We have determined the structures and chromosomal locations of the mouse AR gene (Aldor1) and of two genes highly homologous to Aldor1: the fibroblast growth factor regulated protein gene (Fgfrp) and the androgen regulated vas deferens protein gene (Avdp). The number of introns and their locations in the mouse Aldor1 gene are identical to those of rat and human AR genes and also to those of Fgfrp and Avdp. Mouse Aldor1 gene was found to be located near the Cald1 (Caldesmon) and Ptn (Pleiotropin) loci at the proximal end of chromosome 6. The closely related genes Fgfrp and Avdp were also mapped in this region of the chromosome, suggesting that these three genes may have arisen by a gene duplication event.  (+info)

Transchromosomal mouse embryonic stem cell lines and chimeric mice that contain freely segregating segments of human chromosome 21. (6/2093)

At least 8% of all human conceptions have major chromosome abnormalities and the frequency of chromosomal syndromes in newborns is >0.5%. Despite these disorders making a large contribution to human morbidity and mortality, we have little understanding of their aetiology and little molecular data on the importance of gene dosage to mammalian cells. Trisomy 21, which results in Down syndrome (DS), is the most frequent aneuploidy in humans (1 in 600 live births, up to 1 in 150 pregnancies world-wide) and is the most common known genetic cause of mental retardation. To investigate the molecular genetics of DS, we report here the creation of mice that carry different human chromosome 21 (Hsa21) fragments as a freely segregating extra chromosome. To produce these 'transchromosomal' animals, we placed a selectable marker into Hsa21 and transferred the chromosome from a human somatic cell line into mouse embryonic stem (ES) cells using irradiation microcell-mediated chromosome transfer (XMMCT). 'Transchromosomal' ES cells containing different Hsa21 regions ranging in size from approximately 50 to approximately 0.2 Mb have been used to create chimeric mice. These mice maintain Hsa21 sequences and express Hsa21 genes in multiple tissues. This novel use of the XMMCT protocol is applicable to investigations requiring the transfer of large chromosomal regions into ES or other cells and, in particular, the modelling of DS and other human aneuploidy syndromes.  (+info)

Centrosome amplification and a defective G2-M cell cycle checkpoint induce genetic instability in BRCA1 exon 11 isoform-deficient cells. (7/2093)

Germline mutations of the Brca1 tumor suppressor gene predispose women to breast and ovarian cancers. To study mechanisms underlying BRCA1-related tumorigenesis, we derived mouse embryonic fibroblast cells carrying a targeted deletion of exon 11 of the Brca1 gene. We show that the mutant cells maintain an intact G1-S cell cycle checkpoint and proliferate poorly. However, a defective G2-M checkpoint in these cells is accompanied by extensive chromosomal abnormalities. Mutant fibroblasts contain multiple, functional centrosomes, which lead to unequal chromosome segregation, abnormal nuclear division, and aneuploidy. These data uncover an essential role of BRCA1 in maintaining genetic stability through the regulation of centrosome duplication and the G2-M checkpoint and provide a molecular basis for the role of BRCA1 in tumorigenesis.  (+info)

Phosphorylation of histone H3 is required for proper chromosome condensation and segregation. (8/2093)

Phosphorylation of histone H3 at serine 10 occurs during mitosis in diverse eukaryotes and correlates closely with mitotic and meiotic chromosome condensation. To better understand the function of H3 phosphorylation in vivo, we created strains of Tetrahymena in which a mutant H3 gene (S10A) was the only gene encoding the major H3 protein. Although both micronuclei and macronuclei contain H3 in typical nucleosomal structures, defects in nuclear divisions were restricted to mitotically dividing micronuclei; macronuclei, which are amitotic, showed no defects. Strains lacking phosphorylated H3 showed abnormal chromosome segregation, resulting in extensive chromosome loss during mitosis. During meiosis, micronuclei underwent abnormal chromosome condensation and failed to faithfully transmit chromosomes. These results demonstrate that H3 serine 10 phosphorylation is causally linked to chromosome condensation and segregation in vivo and is required for proper chromosome dynamics.  (+info)

In the pre-implantation embryo, aneuploidy resulting from chromosome segregation error is considered responsible for pregnancy loss. However, only a few studies have examined the relationship between chromosome segregation errors during early cleavage and development. Here, we evaluated this relationship by live-cell imaging using the histone H2B-mCherry probe and subsequent single blastocyst transfer using mouse embryos obtained by in vitro fertilization. We showed that some embryos exhibiting early chromosomal segregation error and formation of micronuclei retained their developmental potential; however, the error affected the blastocyst/arrest ratio. Further, single-cell sequencing after live-cell imaging revealed that all embryos exhibiting micronuclei formation during 1st mitosis showed aneuploidy at the 2-cell stage. These results suggest that early chromosome segregation error causing micronuclei formation affects ploidy and development to blastocyst but does not necessarily cause developmental
程金妹.,李建.,汤济鑫.,郝晓霞.,王志鹏.,...&刘以训.(2017).Merotelic Kinetochore Attachment in Oocyte Meiosis II Causes Sister Chromatids Segregation Errors in Aged Mice.Cell Cycle,16(15),1404-1413 ...
This book describes current knowledge about the mechanisms by which cells segregate their already duplicated chromosomes in preparation for cell division. Experts in the field treat several important aspects of this subject: (1) the history of research on mitotic mechanisms, to serve as a background; (2) assembly of the mitotic spindle; (3) Kinetochore assembly and function; (4) the mechanisms of chromosome congression to the metaphase plate; (5) the spindle assembly checkpoint; (6) mechanisms to avoid and correct erroneous chromosome attachments to the spindle; (7) a molecular perspective on spindle assembly in land plants; (8) chromosome segregation in anaphase A; (9) spindle elongation in anaphase B; and (10) the consequences of errors in chromosome segregation. Each chapter provides the reader with a comprehensive and accurate picture of current research in a form that is both readable and authoritative. The volume is suitable for scholars in this and related fields and for teaching at an ...
Many cancers display both structural (s-CIN) and numerical (w-CIN) chromosomal instabilities. Defective chromosome segregation during mitosis has been shown to cause DNA damage that induces structural rearrangements of chromosomes (s-CIN). In contrast, whether DNA damage can disrupt mitotic processes to generate whole chromosomal instability (w-CIN) is unknown. Here we show that activation of the DNA damage response (DDR) during mitosis selectively stabilizes kinetochore-microtubule (k-MT) attachments to chromosomes through Aurora-A and Plk1 kinases, thereby increasing the frequency of lagging chromosomes during anaphase. Inhibition of DDR proteins, ATM or Chk2, abolishes the effect of DNA damage on k-MTs and chromosome segregation, whereas activation of the DDR in the absence of DNA damage is sufficient to induce chromosome segregation errors. Finally, inhibiting the DDR during mitosis in cancer cells with persistent DNA damage suppresses inherent chromosome segregation defects. Thus, DDR ...
In most bacteria two vital processes of the cell cycle: DNA replication and chromosome segregation overlap temporally. The action of replication machinery in a fixed location in the cell leads to the duplication of oriC regions, their rapid separation to the opposite halves of the cell and the duplicated chromosomes gradually moving to the same locations prior to cell division. Numerous proteins are implicated in co-replicational DNA segregation and they will be characterized in this review. The proteins SeqA, SMC/MukB, MinCDE, MreB/Mbl, RacA, FtsK/SpoIIIE playing different roles in bacterial cells are also involved in chromosome segregation. The chromosomally encoded ParAB homologs of active partitioning proteins of low-copy number plasmids are also players, not always indispensable, in the segregation of bacterial chromosomes ...
Studies of chromosome organization in bacterial cells show that the chromosome is an exquisitely organized and dynamic structure (reviewed recently in Thanbichler et al., 2005). Chromosome segregation in bacteria does not occur all at once but in sequential phases (Lau et al., 2003; Viollier et al., 2004; Bates and Kleckner, 2005; Nielsen et al., 2006). After replication at mid-cell, the origin region (oriC) is rapidly segregated outward. The speed at which this occurs (reviewed in Gordon and Wright, 2000) rules out passive models for bacterial chromosome segregation, which proposed that outward cellular growth could drive the movement of a fixed chromosome. As the loci of the chromosome are replicated, they are moved outward to the poles in a sequential fashion (Lau et al., 2003; Viollier et al., 2004; Bates and Kleckner, 2005; Nielsen et al., 2006). In Escherichia coli, there may be a period of sister chromosome cohesion between duplication and subsequent segregation, although its length is ...
The improper partitioning of chromosomes is responsible for a many human maladies. Errors in mitotic chromosome segregation contribute to the development of cancer while errors in meiosis are the leading cause of birth defects and infertility. Proper chromosome segregation requires the co-ordination of chromosome behavior with other cellular events, and the assembly of a functional machine to move the chromosomes to the right place at the right time in the cell cycle. The research in our laboratory is focused on both the regulatory and mechanical aspects of chromosome behavior. Our projects primarily use the yeast, Saccharomyces cerevisiae, as a model to elucidate conserved aspects of eukaryotic chromosome biology. Our goal is to elucidate fundamentals of chromosome behavior that will provide insights into the origins of chromosome segregation errors in humans.. Our laboratory is involved in two major projects. Slk19 is a bi-functional protein. Slk19 is a member of the FEAR signaling pathway ...
Mitotic chromosome malsegregation produces aneuploidy and genome instability. An increasing number of studies have shown that abnormalities such as aneuploidy and whole-chromosome loss of heterozygosity are commonly present in tumor cells. This suggests that chromosome instability and aneuploidy may play a critical role in tumor development and progression ( Sen, 2000).. The integrity of the cell and of its genome and the correct accomplishment of cellular processes depend on the existence of control points in the cell cycle. These control mechanisms, called `checkpoints, inhibit the transition to the next cell cycle phase if the events of the previous phase have not been correctly executed. A mitotic checkpoint has been identified that controls the metaphase to anaphase transition. A large number of studies have demonstrated that in vertebrates the kinetochore plays an active role in the mitotic checkpoint pathway and that microtubule accumulation at the kinetochore and/or tension that ...
Growth and development are dependent on the faithful duplication of cells. Duplication requires accurate genome replication, the repair of any DNA damage, and the precise segregation of chromosomes at mitosis; molecular checkpoints ensure the proper progression and fidelity of each stage. Loss of an …
Research done in Prof. Sharon Bickels lab has demonstrated that oxidative damage causes a premature loss of sister chromatid cohesion and an increase in chromosome segregation errors in Drosophila oocytes during meiosis. In women, the probability of miscarriage or Down Syndrome increases dramatically with age. Studies of maternal age effect indicate that errors in female meiosis contribute significantly to this age-related effect. The research done by the Bickel lab demonstrates that if oxidative damage contributes to maternal age effect then reducing oxidative damage could be a strategy for reducing chromosome segregation errors during meiosis.. Professor Sharon Bickel, MCB graduate student Adrienne Perkins, Class of 2013 undergraduate researcher Thomas Das and second year MCB graduate student Lauren Panzera contributed to this work. These findings were published in the Proceeding of the National Academy of Sciences: http://www.pnas.org/content/early/2016/10/12/1612047113.full ...
Cells possessing the incorrect number of chromosomes (referred to as aneuploid) can arise as a result of chromosome mis-segregation. Prevention of aneuploidy is especially important in germ cells, as these cells pass genetic information to the next generation, but also in pluripotent cells as these give rise to all tissues and cells of the offspring, including germ cells. Aneuploid conceptions have a detrimental effect on pregnancy outcomes, are surprisingly common in humans (estimated 10-30%), and are a leading cause of miscarriage and developmental disorders. In both meiosis and mitosis, accurate chromosome segregation relies on the correct orientation of sister chromatids during metaphase, which ensures bipolar spindle attachment. Newly replicated sister chromatids are able to align properly on the spindle due to cohesion holding them together. The protein complex responsible for sister chromatid cohesion (SCC) is called cohesin, and has specific subunits depending on its particular role. The ...
Cell cycle: a series of events that occur in cells leading up to their division and replication. Its divided into two main parts, Interphase and a Mitotic or M phase. Interphase is further subdivided into three phases including: G1, S and G2. Each phase has different events occurring within them Cell division: an essential process that occurs in almost all living things. It is characterised by the separation of a cell into two daughter cells. In metazoans, it involves separation of the nucleus and of the cytoplasm Centromere: Confined portion of a mitotic chromosome where sister chromatids are attached and from which kinetochore fibers extend toward a spindle pole. It is essential for correct chromosome segregation during mitosis Chromatin:it is made up of histones, non-histone proteins and DNA which condenses to form eukaryotic chromosomes Chromosome: a single molecule of DNA which is highly organised and tightly packed around proteins (histones) Chromosomal segregation: process by which ...
Cell cycle: a series of events that occur in cells leading up to their division and replication. Its divided into two main parts, Interphase and a Mitotic or M phase. Interphase is further subdivided into three phases including: G1, S and G2. Each phase has different events occurring within them Cell division: an essential process that occurs in almost all living things. It is characterised by the separation of a cell into two daughter cells. In metazoans, it involves separation of the nucleus and of the cytoplasm Centromere: Confined portion of a mitotic chromosome where sister chromatids are attached and from which kinetochore fibers extend toward a spindle pole. It is essential for correct chromosome segregation during mitosis Chromatin:it is made up of histones, non-histone proteins and DNA which condenses to form eukaryotic chromosomes Chromosome: a single molecule of DNA which is highly organised and tightly packed around proteins (histones) Chromosomal segregation: process by which ...
The spindle assembly checkpoint (SAC) prevents chromosome missegregation by coupling anaphase onset with correct chromosome attachment and tension to microtubules. It does this by generating a diffusible signal from free kinetochores into the cytoplasm, inhibiting the anaphase-promoting complex (APC). The volume in which this signal remains effective is unknown. This raises the possibility that cell volume may be the reason the SAC is weak, and chromosome segregation error-prone, in mammalian oocytes. Here, by a process of serial bisection, we analyzed the influence of oocyte volume on the ability of the SAC to inhibit bivalent segregation in meiosis I. We were able to generate oocytes with cytoplasmic volumes reduced by 86% and observed changes in APC activity consistent with increased SAC control. However, bivalent biorientation remained uncoupled from APC activity, leading to error-prone chromosome segregation. We conclude that volume is one factor contributing to SAC weakness in oocytes. ...
Whitehead Institute researchers have determined the organization of a protein complex that is critical during chromosome segregation. Without the solid foundation supplied by this complex, which is called the Constitutive Centromere-Associated Network, the link between chromosome and kinetochore would fail, as would chromosome segregation and cell division.
Chromosome segregation and cell division are essential, highly ordered processes that depend on numerous protein complexes. Results from recent RNA interference screens indicate that the identity and composition of these protein complexes is incompletely understood. Using gene tagging on bacterial artificial chromosomes, protein localization, and tandem-affinity purification-mass spectrometry, the MitoCheck consortium has analyzed about 100 human protein complexes, many of which had not or had only incompletely been characterized. This work has led to the discovery of previously unknown, evolutionarily conserved subunits of the anaphase-promoting complex and the gamma-tubulin ring complex--large complexes that are essential for spindle assembly and chromosome segregation. The approaches we describe here are generally applicable to high-throughput follow-up analyses of phenotypic screens in mammalian cells ...
TY - BOOK ID - 21915 TI - Mechanisms of Mitotic Chromosome Segregation AU - J. Richard McIntosh PY - 2017 SN - 9783038424031 9783038424024 DB - DOAB KW - chromosome segregation, microtubule dynamics, kinetochore, centrosome, genome stability, Cell division, Cell cycle, Cell reproduction, Checkpoints, Cell motility, Inheritance, Microtubules, Cytoskeleton, Cell regulation, Down Syndrome, Trisomies UR - https://www.doabooks.org/doab?func=search&query=rid:21915 AB - This book describes current knowledge about the mechanisms by which cells segregate their already duplicated chromosomes in preparation for cell division. Experts in the field treat several important aspects of this subject: (1) the history of research on mitotic mechanisms, to serve as a background; (2) assembly of the mitotic spindle; (3) Kinetochore assembly and function; (4) the mechanisms of chromosome congression to the metaphase plate; (5) the spindle assembly checkpoint; (6) mechanisms to avoid and correct erroneous chromosome ...
Many cancers have extremely high rates of chromosomal instability (CIN). Some cancers have chromosome segregation errors in every cell division, which would be detrimental to the growth of normal cells. Little is known about how cancers are able to thrive with high levels of CIN. We aim to determine how cells evolve to cope with CIN by creating a model system for persistent chromosomal instability in budding yeast. What types of mutations allow cells to adapt to a constantly shifting genomic content? What are the direct effects of CIN and aneuploidy on the health and viability of cells?. ...
Chromosomes must establish stable biorientation prior to anaphase to achieve faithful segregation during cell division. The detailed process by which chromosomes are bioriented and how biorientation is coordinated with spindle assembly and chromosome congression remain unclear. Here, we provide comp …
The research interests of the participating groups are listed below. Follow the links for more detailed information.. Gustav Ammerer: Signal transduction and transcriptional regulation in yeast. Oliver Bell: Editing the epigenome: plasticity and memory of chromatin structure. Frederic Berger: Histone variants in chromatin structure. Christopher Campbell: Chromosome dynamics. Alexander Dammermann: Centriole assembly and function. Daniel Gerlich: Cytoskeletal and membrane dynamics in cell division. Juraj Gregan: Chromosome segregation during mitosis and meiosis. Verena Jantsch-Plunger: Faithful chromosome segregation in C. elegans meiosis. Franz Klein: Deconstructing the meiotic (yeast) chromosome. Josef Loidl: Meiotic chromosome pairing and recombination. Ortrun Mittelsten Scheid: Epigenetic changes in plants ...
Control of sister chromatid cohesion/separation is critical to ensure faithful chromosome segregation during mitosis and meiosis. Failures in this mechanism during mitosis often lead to aneuploidy and chromosome instability, a major cause of cancer, while failures during meiosis promote miscarriage, birth defects, and infertility in humans. A key protagonist in this control is the cohesin complex, which are composed essentially by four subunits, two of them, called Smc1 and Smc3 (Structural maintenance of chromosomes), are members of a highly conserved protein family also found in prokaryotes and are implicated in various functions related to DNA dynamics, dose compensation, chromosome condensation, recombination, etc. The other two subunits are specific to eukaryotes and, depending on the organism, are termed Scc1/Rad21 or Scc3/STAG, the former mainly for yeast and the latter in higher eukaryotes. In addition to their function in chromatid cohesion during chromosome segregation, our previous ...
DNA replication, transcription, repair, epigenetic inheritance, and chromosome segregation are all processes critical for maintaining cellular viability. In euk...
Author: Hutchins, J. R. A. et al.; Genre: Journal Article; Published in Print: 2010-04-30; Title: Systematic analysis of human protein complexes identifies chromosome segregation proteins.
STUDY QUESTION Are the kinase feedback loops that regulate activation and centromeric targeting of the chromosomal passenger complex (CPC), functional during mitosis in human embryos? SUMMARY ANSWER Investigation of the regulatory kinase pathways involved in centromeric CPC targeting revealed normal phosphorylation dynamics of histone H2A at T120 (H2ApT120) by Bub1 kinase and subsequent recruitment of Shugoshin, but phosphorylation of histone H3 at threonine 3 (H3pT3) by Haspin failed to show the expected centromeric enrichment on metaphase chromosomes in the zygote. WHAT IS KNOWN ALREADY Human cleavage stage embryos show high levels of chromosomal instability. What causes this high error rate is unknown, as mechanisms used to ensure proper chromosome segregation in mammalian embryos are poorly described. STUDY DESIGN, SIZE, DURATION In this study, we investigated the pathways regulating CPC targeting to the inner centromere in human embryos. We characterized the distribution of the CPC in ...
Crumbs (Crb) family proteins are crucial for cell polarity. Recent studies indicate that they are also involved in growth regulation and cancer. However, it is not well-understood how Crb participates in mitotic processes. Here, we report that Drosophila Crb is critically involved in nuclear division by interacting with Xeroderma pigmentosum D (XPD). A novel gene named galla-1 was identified from a genetic screen for crb modifiers. Galla-1 protein shows homology to MIP18, a subunit of the mitotic spindle-associated MMS19-XPD complex. Loss-of-function galla-1 mutants show abnormal chromosome segregation, defective centrosome positions and branched spindles during nuclear division in early embryos. Embryos with loss-of-function or overexpression of crb show similar mitotic defects and genetic interaction with galla-1. Both Galla-1 and Crb proteins show overlapping localization with spindle microtubules during nuclear division. Galla-1 physically interacts with the intracellular domain of Crb. ...
Results: We show that the SMC4 subunit of condensin is encoded by the essential gluon locus in Drosophila. DmSMC4 contains all the conserved domains present in other members of the structural-maintenance-of-chromosomes protein family. DmSMC4 is both nuclear and cytoplasmic during interphase, concentrates on chromatin during prophase, and localizes to the axial chromosome core at metaphase and anaphase. During decondensation in telophase, most of the DmSMC4 leaves the chromosomes. An examination of gluon mutations indicates that SMC4 is required for chromosome condensation and segregation during different developmental stages. A detailed analysis of mitotic chromosome structure in mutant cells indicates that although the longitudinal axis can be shortened normally, sister chromatid resolution is strikingly disrupted. This phenotype then leads to severe chromosome segregation defects, chromosome breakage, and apoptosis ...
Journal of Cell Science is pleased to be a part of the new and exciting Review Commons initiative, launched by EMBO and ASAPbio. Streamlining the publishing process, Review Commons enables high-quality peer review to take place before journal submission. Papers submitted to Review Commons will be assessed independently of any journal, focusing solely on the papers scientific rigor and merit.. ...
Mutations in CDCA7 and HELLS that respectively encode a CXXC-type zinc finger protein and an SNF2 family chromatin remodeler cause immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome types 3 and 4. Here, we demonstrate that the classical nonhomologous end joining (C-NHEJ) proteins Ku80 and Ku70, as well as HELLS, coimmunoprecipitated with CDCA7. The coimmunoprecipitation of the repair proteins was sensitive to nuclease treatment and an ICF3 mutation in CDCA7 that impairs its chromatin binding. The functional importance of these interactions was strongly suggested by the compromised C-NHEJ activity and significant delay in Ku80 accumulation at DNA damage sites in CDCA7- and HELLS-deficient HEK293 cells. Consistent with the repair defect, these cells displayed increased apoptosis, abnormal chromosome segregation, aneuploidy, centrosome amplification, and significant accumulation of γH2AX signals. Although less prominent, cells with mutations in the other ICF genes ...
Mutations in CDCA7 and HELLS that respectively encode a CXXC-type zinc finger protein and an SNF2 family chromatin remodeler cause immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome types 3 and 4. Here, we demonstrate that the classical nonhomologous end joining (C-NHEJ) proteins Ku80 and Ku70, as well as HELLS, coimmunoprecipitated with CDCA7. The coimmunoprecipitation of the repair proteins was sensitive to nuclease treatment and an ICF3 mutation in CDCA7 that impairs its chromatin binding. The functional importance of these interactions was strongly suggested by the compromised C-NHEJ activity and significant delay in Ku80 accumulation at DNA damage sites in CDCA7- and HELLS-deficient HEK293 cells. Consistent with the repair defect, these cells displayed increased apoptosis, abnormal chromosome segregation, aneuploidy, centrosome amplification, and significant accumulation of γH2AX signals. Although less prominent, cells with mutations in the other ICF genes ...
Mutations in CDCA7 and HELLS that respectively encode a CXXC-type zinc finger protein and an SNF2 family chromatin remodeler cause immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome types 3 and 4. Here, we demonstrate that the classical nonhomologous end joining (C-NHEJ) proteins Ku80 and Ku70, as well as HELLS, coimmunoprecipitated with CDCA7. The coimmunoprecipitation of the repair proteins was sensitive to nuclease treatment and an ICF3 mutation in CDCA7 that impairs its chromatin binding. The functional importance of these interactions was strongly suggested by the compromised C-NHEJ activity and significant delay in Ku80 accumulation at DNA damage sites in CDCA7- and HELLS-deficient HEK293 cells. Consistent with the repair defect, these cells displayed increased apoptosis, abnormal chromosome segregation, aneuploidy, centrosome amplification, and significant accumulation of γH2AX signals. Although less prominent, cells with mutations in the other ICF genes ...
MIT biologists have discovered that the environment surrounding a cell plays an integral role in its ability to accurately segregate its chromosomes.
Chromosome segregation during male meiosis is tailored to rapidly generate multitudes of sperm. Little is known about mechanisms that efficiently partition chromosomes to produce sperm. Using live imaging and tomographic reconstructions of spermatocyte meiotic spindles inCaenorhabditis elegans, we find the lagging X chromosome, a distinctive feature of anaphase I inC. elegans males, is due to lack...
early embryonic: 3/5 embryos show spindle related defects, in one of the cases the spindle is hardly visible, in others centration fails or is inaccurate, rocking is missing. This leads to chromosome segregation defects in two of the embryos ...
In a body, every single cell has the same number of chromosomes. This is because when a cell divides, the replicated chromatids are equally segregated into daughter cells. But, the first meiotic division is a clear exception. This division segregates maternal and paternal chromosomes for production of eggs and sperms, which are the origin of a new life. What is the story behind this division?. Read More ...
If you have a question about this talk, please contact Ross Waller.. Host: Mark Carrington. Abstract not available. This talk is part of the Parasitology Seminars series.. ...
An intricate network of proteins ensures the faithful transmission of genetic information through cell generations. The Structural Maintenance of Chromosomes (SMC) protein complex family plays a pivotal role in maintaining genome stability. Initially, the three eukaryotic SMC complexes, cohesin, condensin and Smc5/6 complex (Smc5/6) were identified for their functions in chromosome cohesion, condensation and recombination. Later, it was shown that SMC complexes also control replication and transcription. Another important group of proteins involved in the maintenance of genome stability are the topoisomerases. These enzymes control DNA topology to ensure faithful replication, transcription and chromosome segregation ...
Cancer accounts for over 8 million deaths annually, and current therapies have limited efficacy and adverse side effects. Whereas healthy cells rarely mutate, cancer cells have high rates of genetic instability. This leads to abnormalities in DNA content, such as an aberrant number of chromosomes. Changes in chromosome count are associated with increased tumor growth, resistance to cancer treatments, and worsened patient outcomes. Our goal is to create therapies that exploit this DNA instability to target cancer cells while sparing healthy cells. This would increase the success of therapeutics and mitigate the debilitating side effects associated with many treatments. To achieve this, we study a protein called ATR. ATR has many roles that protect cells from mutation and ensure proper chromosome segregation. Specifically, ATR protects cells from gaining or losing whole chromosomes through a novel function at the centromere, a specialized region of the chromosome that mediates the separation of ...
Michael Goldberg is a Professor in the Department of Molecular Biology and Genetics. Dr. Goldberg is a member of the Graduate Field of Genetics, Genomics and Development and the Graduate Field of Biochemistry, Molecular, and Cell Biology. The Goldberg lab studies the molecular mechanisms which ensure accurate chromosome segregation and other chromosome behaviors.
NIMA in A. nidulans has known functions in G2-M checkpoint control, as does at least one of its mammalian orthologs, Nek2. Nek2 phosphorylates the kinetochore-associated mitotic regulator protein Hec1 and is therefore crucial for faithful chromosome segregation to daughter cells (13) . Our data suggest that Nek1 may be important for sensing, responding to, or repairing DNA damage and thereby for regulating apoptosis and cellular proliferation after injury. When Nek1 is mutated or when its up-regulation is otherwise insufficient, cells are more likely to die aberrantly or fail to proliferate when they normally should. Some cells surviving the insult would also be more likely to pass subtle mutations on to their daughters, which could then accumulate activating oncogenic or inactivating tumor suppressor mutations. Up-regulation of Nek1 may be a defensive response to cellular and DNA injury, a response to prevent excessive or unscheduled apoptosis. If so, we predict that Nek1 might be overexpressed ...
Classical simulations are described of the fully relaxed surface lattice structures of the five lowest-index planes of α-Al20 3 and the resulting crystal morphology. The surface coverage by yttrium and magnesium as a function of temperature is evaluated on the basis of a non-Arrhenius isotherm and calculated heats of surface segregation. The calculated morphology, surface coverages and heats of segregation are compared with experiment. A quantum simulation of a relaxed {0001} surface is presented and the surface structure and energy compared with the classical results. Estimates are made of the adsorption energy of HF at the {0001} surface. ...
Diagnostic screening allows medical practitioners to identify diseases caused by defective chromosomes, genes or proteins. This screening can occur pre-natally (before birth), pre-symptomatically (before symptoms develop) or be used to confirm a suspected diagnosis. ...
early embryonic: Very reproducible, robust phenotype. Pronuclei and nuclei are smaller or barely visible. Interaction between pronuclei can be impaired, spindle is thin and tends to bend during rocking and elongation in P0. This results in chromosome mis-segregation (leading to karyomeres), or even absence of spindle, and furrow regression at cytokinesis. Beautiful ...
This spindle has a few problems because a number of chromosomes are attached to only one of the spindle poles. These types of attachments are dangerous because they will lead to mis-segregation of the genome during cell division.. ...
Self-Placing Concrete segregation set of tests - Béton Auto-Plaçant ensemble dessais de ségrégation (). The Forney Column Segregation Test Set contains everything needed to determine the potential segregation of coarse aggregate in SCC mixtures tes
Supplementary MaterialsSupplementary Information 41467_2020_16997_MOESM1_ESM. genome cancer and instability. locus on chromosome XV17. Significantly, this system actions frequencies of noncrossover (NCO) and CO in DSB restoration, and in addition distinguishes between brief and long-tract GC (Fig.?1a; Supplementary Fig.?1). Upon I-gene and segregation: white (and deletion was proven to boost DSB-induced chromosome reduction occasions inside a different hereditary program, because of abortive BIR occasions14 possibly. To verify if the alteration from the HR restoration might be due to early chromosome segregation in deletion seriously affected BIR, from the cell-cycle stage irrespective, confirming our earlier observation how the BIR defect of will be faulty in BIR for yet another reason than lacking signalling to Pif1. Open up in another windowpane Fig. 2 Rad9 promotes DSB repair through BIR.a Scheme of the genetic system to test BIR in JRL092 background. b Southern blot of deletion increased ...
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Errors in chromosome segregation in mammalian oocytes lead to aneuploid eggs that are developmentally compromised. In mitotic cells, mitotic centromere associated kinesin (MCAK; KIF2C) prevents chromosome segregation errors by detaching incorrect microtubule-kinetochore interactions. Here, we examine whether MCAK is involved in spindle function in mouse oocyte meiosis I, and whether MCAK is necessary to prevent chromosome segregation errors. We find that MCAK is recruited to centromeres, kinetochores and chromosome arms in mid-meiosis I, and that MCAK depletion, or inhibition using a dominant-negative construct, causes chromosome misalignment. However, the majority of oocytes complete meiosis I and the resulting eggs retain the correct number of chromosomes. Moreover, MCAK-depleted oocytes can recover from mono-orientation of homologous kinetochores in mid-meiosis I to segregate chromosomes correctly. Thus, MCAK contributes to chromosome alignment in meiosis I, but is not necessary for ...
Heterochromatin protein 1 is associated with centromeric heterochromatin in Drosophila, mice, and humans. Loss of function mutations in the gene encoding heterochromatin protein 1 in Drosophila, Suppressor of variegation2-5, decrease the mosaic repression observed for euchromatic genes that have been juxtaposed to centromeric heterochromatin. These heterochromatin protein 1 mutations not only suppress this position-effect variegation, but also cause recessive embryonic lethality. In this study, we analyze the latter phenotype in the hope of gaining insight into heterochromatin function. In our analyses of four alleles of Suppressor of variegation2-5, the lethality was found to be associated with defects in chromosome morphology and segregation. While some of these defects are seen throughout embryonic development, both the frequency and severity of the defects are greatest between cycles 10 and 14 when zygotic transcription of the Suppressor of variegation2-5 gene apparently begins. By this time ...
Lagging chromosomes during anaphase are an easily assayed and therefore commonly reported mitotic defect. However, in most cases, the mechanisms that give rise to lagging chromosomes are unknown. Lagging chromosomes can be caused by asbestos fibers (Hersterberg and Barrett, 1985), elevated ras p21 expression (Hagag et al., 1990), carcinogens such as diethylstilbestrol (Schiffmann and De Boni, 1991), and inherited genetic conditions such as Roberts syndrome (Jabs et al., 1991). Chromosomes, chromatids, and chromosome fragments that do not segregate properly often end up spatially separated from the bulk of the chromosomes and will reform a separate nuclear envelope after mitosis is completed. This results in a cell containing micronuclei. Sometimes these cells are described as multinucleate. Severe chromosome segregation defects will in turn inhibit cytokinesis giving rise to truly multinucleate cells (Schultz and Onfelt, 1994). The mechanism by which these diverse agents disrupt anaphase ...
It is likely that with age, microtubule-kinetochore attachment errors increase. This is inferred by the raised numbers of lagging chromosomes during anaphase in aged oocytes. Their presence failed to alter segregation dynamics, implying that they have no influence on the activity of the SAC. Lagging chromosomes are most likely generated by increased incorrect microtubule attachment, which would have been promoted by reduced cohesion, a conclusion supported by the finding of univalents, weakly attached bivalents, raised interkinetochore distance, and reduced SGO2 on kinetochores in aged oocytes seen in this study. It may be that lowered chromosome cohesion, measured here and in other aging mouse and human oocyte studies (Chiang et al., 2010; Lister et al., 2010; Duncan et al., 2012; Merriman et al., 2012), allows greater flexibility within a sister kinetochore pair, so promoting incorrect attachment. Indeed, the importance of rigidity in bivalent structure for their faithful segregation at MI, in ...
Accurate segregation of meiotic chromosomes requires that sister-chromatids remain physically associated from the time of their synthesis during S phase until they segregate toward opposite poles at anaphase II. In Drosophila melanogaster meiosis, physical association of sister chromatids, known as sister-chromatid cohesion, requires the protein product of the orientation disruptor (ord) gene. Genetic and cytological analyses of ord mutants indicate that sister chromatids separate precociously in the absence of ORD activity, resulting in random chromosome segregation during both meiotic divisions. To understand the molecular basis of ORD activity more fully, we localized ORD protein in Drosophila spermatocytes using immunofluorescence and demonstrate that ORD associates with centromeres of meiotic chromosomes from early G2 through anaphase II. Maintenance of ORD at centromeres until anaphase II requires functional MEI-S332 protein, as centromeric ORD signal disappears during anaphase I in ...
The IPL1 gene is required for high-fidelity chromosome segregation in the budding yeast Saccharomyces cerevisiae. Conditional ipl1ts mutants missegregate chromosomes severely at 37 degrees C. Here, we report that IPL1 encodes an essential putative protein kinase whose function is required during the later part of each cell cycle. At 26 degrees C, the permissive growth temperature, ipl1 mutant cells are defective in the recovery from a transient G2/M-phase arrest caused by the antimicrotubule drug nocodazole. In an effort to identify additional gene products that participate with the Ipl1 protein kinase in regulating chromosome segregation in yeast, a truncated version of the previously identified DIS2S1/GLC7 gene was isolated as a dosage-dependent suppressor of ipl1ts mutations. DIS2S1/GLC7 is predicted to encode a catalytic subunit (PP1C) of type 1 protein phosphatase. Overexpression of the full-length DIS2S1/GLC7 gene results in chromosome missegregation in wild-type cells and exacerbates the ...
Microtubules segregate chromosomes by attaching to macromolecular kinetochores. Only microtubule-end attached kinetochores can be pulled apart; how these end-on attachments are selectively recognised and stabilised is not known. Using the kinetochore and microtubule-associated protein, Astrin, as a molecular probe, we show that end-on attachments are rapidly stabilised by spatially-restricted delivery of PP1 near the C-terminus of Ndc80, a core kinetochore-microtubule linker. PP1 is delivered by the evolutionarily conserved tail of Astrin and this promotes Astrins own enrichment creating a highly-responsive positive feedback, independent of biorientation. Abrogating Astrin:PP1-delivery disrupts attachment stability, which is not rescued by inhibiting Aurora-B, an attachment destabiliser, but is reversed by artificially tethering PP1 near the C-terminus of Ndc80. Constitutive Astrin:PP1-delivery disrupts chromosome congression and segregation, revealing a dynamic mechanism for stabilising ...
Mitosis is a key event in the life of a cell, where duplicated chromosomes are separated into the daughter cells. Defects associated with chromosome segregation can lead to aneuploidy, a hallmark of cancer. Chromosome segregation is achieved by the mitotic spindle, which is composed of microtubules (MTs), motors and microtubule associated protein (MAPs). Motors such as kinesins generate forces within the spindle while MAPs perform functions such as organize the spindle pole and maintain the bipolar spindle. Both motors and MAPs contribute to spindle mechanics. Here I used the relatively simple fission yeast to address how defects in spindle mechanics affect chromosome segregation. The metaphase spindle is maintained at a constant length by an antagonistic force-balance model yet how the regulation of metaphase spindle length contribute to subsequent chromosome segregation remains unexplored. To test the force-balance model, I applied gene deletion and fast microfluidic temperature-control with live-cell
Accurate chromosome segregation in mitosis is required to maintain genetic stability. hZwint-1 [human Zw10 (Zeste white 10)-interacting protein 1] is a kinetochore protein known to interact with the kinetochore checkpoint protein hZw10. hZw10, along with its partners Rod (Roughdeal) and hZwilch, form a complex which recruits dynein-dynactin and Mad1-Mad2 complexes to the kinetochore and are essential components of the mitotic checkpoint. hZwint-1 localizes to the kinetochore in prophase, before hZw10 localization, and remains at the kinetochore until anaphase, after hZw10 has dissociated. This difference in localization timing may reflect a role for hZwint-1 as a structural kinetochore protein. In addition to hZw10, we have found that hZwint-1 interacts with components of the conserved Ndc80 and Mis12 complexes in yeast two-hybrid and GST (glutathione transferase) pull-down assays. Furthermore, hZwint-1 was found to have stable FRAP (fluorescence recovery after photobleaching) dynamics similar ...
In humans, early embryo development is a complex process that consists of sequential events: oocyte maturation, fertilization, embryonic growth and implantation. Disruption of these highly regulated processes results in reproductive failure and infertility. This study characterizes and describes embryonic aneuploidy, mitochondrial content level and endometrial microbial environment related to reproductive competence, in particular instances in which failure results. To examine the molecular underpinnings of mammalian gamete and early embryo chromosome segregation, we established a comprehensive chromosomal screening (CCS) method for mice poly bodies, oocytes and embryos by the application of whole genome amplification (WGA) and next generation sequencing (NGS). First, we validated this approach using single mouse embryonic fibroblasts engineered to have stable trisomy 16. We further validated this method by identifying reciprocal chromosome segregation errors in the products of meiosis I (gamete and
Looking for chromosome congression? Find out information about chromosome congression. congression Explanation of chromosome congression
Akiyoshi, B., and S. Biggins. Reconstituting the Kinetochore-Microtubule Interface: What, Why, and How. Chromosoma, 2012, pp. 1-16 ...
It will be capable of destabilising defective non-bipolar attachments and as this kind of functions as an errorcorrection component that assures faithful segregation of sister chromatids. Merotelic chromosome attachments Merotely is surely an attachment state during which a single kinetochore attaches to microtubules from each poles. Merotelic attachments happen usually in early mitosis and when left uncorrected they induce anaphase lagging chromosomes and may lead to aneuploidy . The vast majority of merotelic attachments are resolved in prometaphase and latest scientific studies identified a serious function for Aurora-B in this correction operation. Aurora-B gets enriched at centromeres of merotelically attached kinetochores wherever it promotes kinetochoremicrotubule turnover more than likely via regulation of MCAK. Aurora-B influences the function of MCAK at several amounts. To start with, Aurora-B action is needed for your concentration of MCAK on centromeres ...
Neoplastic cells are genetically unstable. Strategies that target pathways affecting genome instability can be exploited to disrupt tumor cell growth potentially with limited consequences to normal cells. Chromosomal instability (CIN) is one type of genome instability characterized by mitotic defects that increase the rate of chromosome mis-segregation. CIN is frequently caused by extra centrosomes that transiently disrupt normal bipolar spindle geometry needed for accurate chromosome segregation. Tumor cells survive with extra centrosomes because of biochemical pathways that cluster centrosomes and promote chromosome segregation on bipolar spindles. Recent work shows that targeted inhibition of these pathways prevents centrosome clustering and forces chromosomes to segregate to multiple daughter cells, an event triggering apoptosis that we refer to as anaphase catastrophe. Anaphase catastrophe specifically kills tumor cells with more than two centrosomes. This death program can occur after ...
Aneuploidy is the leading cause of pregnancy loss and birth defects in humans. At least 5% of all recognized pregnancies are aneuploid. Maternal meiosis is especially error-prone and the rate of chromosome missegregation increases exponentially with advancing maternal age. Despite its clinical significance, the mechanisms underlying maternal age-dependent segregation errors are not understood. One hypothesis is that cohesion deteriorates with advancing maternal age and homologous chromosomes that do not maintain chaismata segregate randomly during meiosis. With Drosophila as a model organism, I have used techniques developed in our laboratory to experimentally age oocytes. To accelerate loss of cohesion with age, I utilized mutant flies with slightly compromised meiotic cohesion. A standard genetic test was utilized to assess errors in meiotic chromosome segregation after oocytes were subjected to the aging regimen. My objective was to determine whether aging of oocytes with slightly compromised ...
Egg infertility is a predisposition to miscarriages, infertility, and trisomic pregnancies caused by increased frequency of chromosome segregation errors in the eggs of women of advanced maternal age (AMA). Egg infertility is now a significant public health issue, with 1 in 5 US women now attempting her first pregnancy after age 35. Increased rates of egg infertility temporally coincide with rising levels of FSH that occur with age. By age 42, up to 87% of embryos are aneuploid, and 40-50% of women experience egg infertility. An Introductory Editorial will present an overview of causative factors and potential therapeutic strategies to prevent egg aneuploidy and infertility. Papers in series will be comprised of data drawn from studies performed both in animals and in humans. Part I will discuss endocrine and other molecular changes implicated in the pathogenesis of AMA oocyte aneuploidy and infertility. Section 1 will discuss defects that emerge with age in controlling the fidelity of meiotic oocyte
Many cancers have extremely high rates of chromosomal instability (CIN). Some cancers have chromosome segregation errors in every cell division, which would be detrimental to the growth of normal cells. Little is known about how cancers are able to thrive with high levels of CIN. We aim to determine how cells evolve to cope with CIN by creating a model system for persistent chromosomal instability in budding yeast. What types of mutations allow cells to adapt to a constantly shifting genomic content? What are the direct effects of CIN and aneuploidy on the health and viability of cells? close ...
CASC5 [ENSP00000335463]. Cancer susceptibility candidate gene 5 protein; Performs two crucial functions during mitosis: it is essential for spindle-assembly checkpoint signaling and for correct chromosome alignment. Required for attachment of the kinetochores to the spindle microtubules. Directly links BUB1 and BUB1B to kinetochores. Part of the MIS12 complex, which may be fundamental for kinetochore formation and proper chromosome segregation during mitosis. Acts in coordination with CENPK to recruit the NDC80 complex to the outer kinetochore.. Synonyms: CASC5, CASC5p, hCASC5, H0YN41, KNL1 .... Linkouts: STRING Pharos UniProt OMIM ...
The kinetochore provides the connection between chromosomes and spindle microtubules. Defining the molecular architecture of the core kinetochore components is critical for understanding the mechanisms by which the kinetochore directs chromosome segregation. The KNL1/Mis12 complex/Ndc80 complex (KMN) network acts as the primary microtubule-binding interface at kinetochores, and provides a platform for recruitment of regulatory proteins. The results in this thesis demonstrate that the CENP-C and CENP-T inner kinetochore receptors form separate scaffolds for KMN network assembly. Initial biochemical results suggested a non-canonical assembly pathway mediated by a direct interaction between CENP-T and the Ndc80 complex. These results were further verified and expanded upon in cells using an ectopic targeting approach to allow careful analysis of the pathways independently of one another. The data presented here demonstrate that in addition to forming two pathways, the CENP-C and CENP-T based ...
Meiotic chromosome segregation must occur with high fidelity in order to prevent the generation of deleterious aneuploidies. In meiosis I, homologous chromosomes pair, then migrate to opposite poles of the spindle. This process uses a collection of unique structures and mechanisms that have yet to be thoroughly characterized. To acquire a collection of informative meiotic mutants, we carried out a novel genetic screen in Saccharomyces cerevisiae. This screen was designed to identify dominant mutants in which meiosis I chromosome segregation occurs with decreased fidelity. One mutant recovered using this screen, SID1-1 (sister disjunction), showed an incidence of spores disomic for a marked chromosome III that was 25-fold greater than the wild-type level. Crossing-over is slightly, but not dramatically, reduced in SID1-1. Both recombinant and nonrecombinant chromosomes segregate with reduced fidelity in the presence of SID1-1. We present evidence that the mutant is defective in sister-chromatid ...
Meiosis is the process of specialized divisions that produce haploid gametes from diploid cells. Meiotic chromosome distribution is a critical event in sexual reproduction. Failure of chromosome segregation during meiosis results in progeny that are aneuploid, possessing chromosomes above or below the 2N number of the diploid genome. Such failures have many important consequences, not least of which is the high rate of aneuploid oocyte production in mammals, a central cause of human infertility, miscarriages, and birth defects (Bennabi et al., 2016). Beaven et al. examined the role of Drosophila melanogaster 14-3-3 proteins in meiotic chromosome segregation and found that they promote accurate assembly of meiotic spindles through spatial regulation of claret nondisjunctional (Ncd), a minus end-directed kinesin-14 family motor protein that mediates sliding of antiparallel microtubules and cross-links parallel microtubules (Fink et al., 2009). This inhibition is relieved locally through ...
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated ...
Here, we found that SphK1 and its product S1P regulate mitosis. SphK1 promoted proper mitotic progression in a SAC-dependent manner, whereas increased SphK1 activity accelerated mitosis (Movie S1 and Movie S2). S1P overrode the mitotic spindle checkpoint, led to premature mitotic exit, and induced chromosome segregation defects through a pathway involving S1P5 and phosphatidylinositol 3-kinase (PI3K)-AKT signaling that was at least partially mediated by Polo-like kinase 1 (PLK1).. In summary, our study uncovers a previously unknown role for SphK1-S1P-S1P5 signaling in controlling proper mitotic progression through prometaphase to the metaphase-to-anaphase transition. More generally, our findings support the concept that cellular micro- environment plays an important role in coordination of mitosis and paves the way for future studies evaluating the relationship between extracellular signals, mitotic progression, and chromosomal stability.. ...
Altered expressions and/or mutations of cell cycle regulators result in the development of cancer (1 , 34) . Disruption of mitotic checkpoints can result in abnormal nuclei, missegregated chromosomes, and aneuploidy (35 , 36) . Among the most notable abnormalities commonly found in tumor cells are chromosomal rearrangements and changes in chromosome number (4, 5, 6) . This property of cancer cells is important, especially for our understanding of the regulatory mechanisms that control the progression of malignancy. In colorectal tumors without microsatellite instability, for example, a defect in chromosome segregation results in gains or losses in excess of 10− 2/chromosome/segregation (6) . Although the precise mechanisms by which duplicated chromosomes are equally segregated during mitosis are largely unknown, the centrosome is believed to play an important role(s) in the formation of bipolar spindles. Mutations in fly aurora and yeast IPL1 are responsible for a chromosomal segregation ...
Chromosomes, which are the vehicles of genetic heredity, have to be duplicated in S-phase and equally segregated into daughter cells during M-phase in the cell cycle progression. One of crucial factors, which ensure the accurate chromosome segregation, is the kinetochore that is a large protein complex assembled on the centromere of each chromosome. The kinetochore binds to spindle microtubules and connects with chromosomes. Defects in the kinetochore results in chromosome missegregation, leading to aneuploidy that causes genetic disorders including cancer. Therefore, understanding of structure and function of the kinetochore is important not only for preventing from the genetic disorders but also for answering a fundamental biological question how are chromosomes accurately segregated ...
Defective segregation of chromosomes during cell division causes aneuploidy and is a characteristic feature of cancer cells. Cells therefore utilize multiple mechanisms to ensure faithful segregation and prevent aneuploidy, including phospho-regulation of proteins responsible for separating replicated chromosomes during mitosis. These mechanisms depend on the essential, conserved protein kinase Mps1. The goal of my work is to identify the downstream effectors of Mps1 in chromosome segregation and to illuminate the mechanisms of Mps1 function. This work will combine novel biochemical and cell biological approaches with emerging structural analysis methods to improve fundamental understanding of phospho-regulation of chromosome segregation.. ...
Protein kinase which plays an important role in mitotic cell cycle progression. Required for chromosome segregation at metaphase-anaphase transition, robust mitotic spindle formation and cytokinesis. Phosphorylates ATF4, CIR1, PTN, RAD26L, RBBP6, RPS7, RPS6KB1, TRIP4, STAT3 and histones H1 and H3. Phosphorylates KIF11 to promote mitotic spindle formation. Involved in G2/M phase cell cycle arrest induced by DNA damage. Inhibition of activity results in apoptosis. May contribute to tumorigenesis by suppressing p53/TP53-induced cancer cell senescence ...
Tight regulation of histone relative stoichiometry and overall levels is fundamental to the preservation of genome integrity in all eukaryotes. Abnormal histone levels induce defects in mitotic chromosome segregation, chromatin structure, and transcription and lead to loss of viability (Meeks-Wagner and Hartwell 1986; Han et al. 1987; Clark-Adams et al. 1988; Kim et al. 1988; Norris et al. 1988). Defects in chromatin structure caused by inactivation of nucleosome assembly factors cause high rates of chromosomal rearrangements and spontaneous DNA damage and elicit checkpoint activation (Myung et al. 2003; Ye et al. 2003; Ramey et al. 2004).. This study provides genetic and biochemical evidence that Trf4 and Trf5 make a redundant contribution to genome stability in yeast through control of histone mRNA levels during S phase. We show that the mRNAs coding for the four core histones, but not other cell cycle-regulated transcripts tested, accumulate to abnormally high levels in S phase in a trf4-ts ...
Plant reproduction depends on proper development of the male and the female gametophyte. Due to the reduced size of the angiosperm gametophyte and especially inaccessibility of the female gametophyte, it is challenging to study these fundamental processes. Recent advances in microdissection techniques combined with powerful tools for transcriptome analysis have begun to shed a light on molecular mechanisms underlying the processes. The aim of this thesis was to functionally characterize a maize MATH-BTB (ZmMAB1) protein, which was encoded by a gene highly represented in cDNA libraries of isolated maize egg cells and zygotes. A phylogenetic analysis has shown that ZmMAB1 belongs to an expended group of a previously undescribed maize MATH-BTB gene family with 31 members. RNAi silencing of ZmMAB1 leads to chromosome segregation defects and short spindles during male meiosis. After meiosis-mitosis transition two identical nuclei are formed in mab1 (RNAi) mutants disrupting male and female germline ...
As there were residual levels of SMC6 detected in the oocytes isolated from juvenile Smc5 cKO mice, it was hypothesized that SMC5/6 levels were adequate to facilitate chromosome segregation during meiosis, but was insufficient for sustaining proper mitotic segregation during the early embryogenesis. To further assess the relationship between Smc5 mutation and the capacity to form mature blastocysts, wild-type, heterozygous Smc5 del male and female mice were used for IVF to test effects of paternal versus maternal inheritance of the mutant allele. The oocytes used in these assays were from 4-week-old mice, and therefore equivalent to the designated juvenile age group. In addition, Smc5 cKO male mice (Smc5 flox/del, Hspa2-Cre tg/0), which are fertile and produce sperm that almost exclusively carry the Smc5 del allele, were used for IVF. Based on mating tests with C57BL6/J wild-type females, 98% of progeny from the Smc5 flox/del, Hspa2-Cre males carry the Smc5 del allele (Table 3). When sperm ...
Research conducted in the lab of Associate Professor Jakob Nilsson now provides novel insight into how the cell secures accuracy in this process. Postdoc Gang Zhang investigated how the BubR1 protein functions in the cell, particularly its role at a structure on chromosomes called kinetochores. He found that BubR1 binds to kinetochores in two different ways and that this affects its function. This was a surprising result as previous work had always anticipated only one way that BubR1 binds kinetochores explains Gang Zhang. In collaboration with Blanca Lopez Mendez from the CPR Biophysics facility the molecular basis of the two BubR1 populations was established by combining biophysical measurements and advanced imaging techniques. Using this information it was possible to investigate the function of the two different pools of BubR1 and show that one pool helps establish the connection between kinetochores and microtubules and the other pool controls when the chromosomes should split into the ...
The putative chromatin remodeling enzyme Plk1-interacting checkpoint helicase (PICH) was uncovered as an interaction partner and substrate of the mitotic kinase Plk1. is required for prevention of chromatin bridge formation but not for UFB resolution, and quantitative analyses of UFB and chromatin bridge frequencies suggest that PIK-293 these structures are of different etiologies. We also show that this ATPase activity of PICH is required for temporal and spatial control of PICH localization to chromatin and that Plk1 likely controls PICH localization through phosphorylation of proteins unique from PICH itself. This work strengthens the view that PICH is an important, Plk1-regulated enzyme, whose ATPase activity is essential for maintenance of genome integrity. Although not required for the spindle assembly checkpoint, PICH is clearly important for faithful chromosome segregation. Electronic supplementary material The online version of this article (doi:10.1007/s00412-012-0370-0) contains ...
Essential roles of Drosophila inner centromere protein (INCENP) and aurora B in histone H3 phosphorylation, metaphase chromosome alignment, kinetochore disjunction, and chromosome segregation ...
Monolayers of Xenopus tissue culture cells (XTC) were grown in 66% Leibovitz L-15 media containing 10% fetal calf serum, 1mM sodium pyruvate and antibiotics at ~21°C. Mitotic chromosomes were purified from XTC cells after a 16 hour block in 10µg/ml vinblastine (Sigma-Aldrich). Chromosomes were purified as previously described with minor modifications (Wordeman et al., 1991). Experiments were preformed essentially as described (Mitchison and Kirschner, 1985). Purified mitotic chromosomes were diluted in reactions containing 10 µM tubulin in BRB80 buffer plus 1mM GTP. Reactions were incubated at 37°C for 15 minutes in a water bath and were fixed with 10mM EGS (ethyleneglycol-bis-succinimidyl-succinate) dissolved in BRB80 for 10 minutes at 37°C. Reactions were layered onto a 30% glycerol cushion prepared in BRB80 and chromosome-microtubule complexes were pelleted through the cushion onto poly-l-lysine coated coverlslips. Coverslips were post fixed with ice-cold methanol for 5 minutes at 4°C, ...
Reproductive cells that are destined to become sperm or egg undergo meiotic division during which the chromosome number is halved. As Sluder and McCollum explain in their Perspective, new findings ( Shonn et al.) in yeast show that there is a spindle checkpoint that operates during meiosis to ensure that an equal number of replicated chromosomes arrives at each pole of the cell. One of the components of this meiotic spindle checkpoint turns out to be Mad2, which gives the signal to halt meiosis if it looks like unequal chromosome segregation is taking place. ...
Inequality and social segregation are important topics in Economics. In this research, I study how inequality in primary school performance is driven by role models, and the extent to which children relate to them via gender and ethnicity. I run an experiment in English primary schools with random allocation to a role model intervention during exam preparation period in spring term. The treatment aims at raising self-efficacy for and providing information on the usefulness of Maths. The interventions occurred as video recordings of TED Talk-like speeches by successful STEM professionals of different gender and ethnicity. To measure the effect of role models on Maths attainment, I consider performance in standardized Maths tests two months after the intervention. I find positive effects on performance of pupils who watched a video of a speaker of the same gender. The effect is significant compared to seeing an opposite gender speaker, and no speaker at all in the control group. The effect of same ...
Chromosome instability (CIN) is an inherent enabling characteristic of cancer important for tumor initiation and progression and is observed in a majority of tumors (1⇓-3). It has been proposed that alterations resulting in genome instability happen early during tumor formation, allowing the accumulation of errors during DNA replication, repair, and chromosome segregation, thereby increasing the likelihood that a cell will acquire multiple genetic changes necessary for tumor progression (4). CIN is possibly the major contributor to intratumoral heterogeneity-that is, the presence of genetically distinct populations of cells within a single tumor that impacts treatment strategy, drug resistance, and tumor evolution (5⇓⇓-8). For these reasons, defining genes and pathways that drive CIN and understanding the mechanisms that underlie genome stability will contribute not only to an understanding of tumor etiology and progression but will also be relevant for guiding therapeutic strategies. The ...
Binary fission can refer to cell division in bacteria. Bacteria replicate their chromosomes prior to division, but I dont think that state can be called diploid because the chromosomes are identical. Diploid organisms can be carrying different alleles on each pair of sister chromosomes, but this is not the case for a duplicated bacterial chromosome before cell division. Therefore in my opinion your statement is not necessarily true, at least for bacteria ...
You are cordially invited to the EMBO Workshop on Chromosome Segregation and Aneuploidy, to be held on June 22-26, 2013, on the estate of Nyenrode Castle in Breukelen, The Netherlands ...
Hirano, M., Anderson, D. E., Erickson, H. P., Hirano, T. (2001) Bimodal activation of SMC ATPase by intra- and inter-molecular interactions. Embo Journal, 20 (12). pp. 3238-3250. ISSN 0261-4189 Hirano, T. (2000) Chromosome cohesion, condensation, and separation. Annual Review of Biochemistry, 69. pp. 115-144. ISSN 0066-4154 Hirano, T. (2004) Chromosome shaping by two condensins. Cell Cycle, 3 (1). pp. 26-8. ISSN 1538-4101 (Print) Hirano, T. (2005) Condensins: organizing and segregating the genome. Curr Biol, 15 (7). R265-75. ISSN 0960-9822 (Print) Hirano, T. (2005) SMC proteins and chromosome mechanics: from bacteria to humans. Philos Trans R Soc Lond B Biol Sci, 360 (1455). pp. 507-14. ISSN 0962-8436 (Print) Hirano, T., Kobayashi, R., Hirano, M. (1997) Condensins, chromosome condensation protein complexes containing XCAP-C, XCAP-E and a Xenopus homolog of the Drosophila Barren protein. Cell, 89 (4). pp. 511-21. ISSN 0092-8674 (Print) ...
an animal cell consists of 46 post-mitotic chromosomes in each of its somatic cells. explain how many chromosomes must, Hire Biology Expert, Ask Academics Expert, Assignment Help, Homework Help, Textbooks Solutions
Alle Zellen müssen ihr Erbmaterial verdoppeln und dafür Sorge tragen, daß jede Tochterzelle einen kompletten Satz des Erbguts vor der Zellteilung erhält. In Bakterien müssen die Chromosomen organisiert und kompaktiert werden, während sie gleichzeitig dynamisch sein müssen, um laufend.... Full description. ...
Chromosome segregation during meiosis[edit]. Segregation of homologous chromosomes to opposite poles of the cell occurs during ... Proper segregation is essential for producing haploid meiotic products with a normal complement of chromosomes. The formation ... However, in the fission yeast Schizosaccharomyces pombe, when chiasmata are absent, dynein promotes segregation.[22] Dhc1, the ... Dynein is involved in the movement of chromosomes and positioning the mitotic spindles for cell division.[2][3] Dynein carries ...
... and initiates chromosome dimer segregation. The dif site is found at the intersection between the monomers of the chromosome ... FtsK is a 1329 amino acid protein involved in bacterial cell division and chromosome segregation. FtsK stands for "Filament ... Bigot S, Sivanathan V, Possoz C, Barre FX, Cornet F (June 2007). "FtsK, a literate chromosome segregation machine". Molecular ... Pogliano K, Pogliano J, Becker E (December 2003). "Chromosome segregation in Eubacteria". Current Opinion in Microbiology. 6 (6 ...
In late anaphase, chromosomes also reach their overall maximal condensation level, to help chromosome segregation and the re- ... Santaguida S, Amon A (August 2015). "Short- and long-term effects of chromosome mis-segregation and aneuploidy". Nature Reviews ... In this stage, chromosomes are long, thin, and thread-like. Each chromosome has two chromatids. The two chromatids are joined ... Blow JJ, Tanaka TU (November 2005). "The chromosome cycle: coordinating replication and segregation. Second in the cycles ...
Specifically, Draviam monitors chromosome microtubule attachment, end-on conversion, chromosome mis-segregation and how cells ... Dravian, Viji Mythily; Sorger, Peter (2004). "Chromosome segregation and genomic stability". Current Opinion in Genetics & ... progression The ch-TOG/XMAP215 protein is essential for spindle pole organization in human somatic cells Chromosome segregation ... Aneuploidy describes the situation where a cell contains an abnormal number of chromosomes, and often occurs in aggressive ...
Badrinarayanan, Anjana; Le, Tung B. K.; Laub, Michael T. (2015-11-13). "Bacterial Chromosome Organization and Segregation". ... No NTPase This system is also used by most bacteria for chromosome segregation. Type I partition systems are composed of an ... The StbA-stbDRs complex may be used to pair plasmid the host chromosome, using indirectly the bacterial partitioning system. ... Guynet C, de la Cruz F (2011). "Plasmid segregation without partition". Mobile Genetic Elements. 1 (3): 236-241. doi:10.4161/ ...
This point in the cell will block the segregation of chromosomes until all of the chromosomes are properly connected. It also ... Mechanisms of mitotic chromosome segregation. [Place of publication not identified]: MDPI AG. 2017. ISBN 978-3-03842-402-4. ... In 2017, McIntosh is the guest editor of Mechanisms of Mitotic Chromosome Segregation. In this work, McIntosh connects various ... Here, the researchers applied these findings to chromosome segregation and concluded that the microtubule dynamics create the ...
"Deregulation of Chromosome Segregation and Cancer". Annual Review of Cancer Biology. 4: 257-278. doi:10.1146/annurev-cancerbio- ... It is required for two microtubule-dependent processes: nuclear movement prior to anaphase, and chromosome separation. CDC20, ...
"Error-prone chromosome-mediated spindle assembly favors chromosome segregation defects in human oocytes". Science. 348 (6239): ... Mogessie, Binyam; Schuh, Melina (2017). "Actin protects mammalian eggs against chromosome segregation errors". Science. 357 ( ... in which oocytes mature into eggs by extruding half of their chromosomes in a small cell termed the polar body. This requires ... increasing the likelihood of segregation errors. She has also investigated the reasons why the children of older mothers have a ...
Jallepalli PV, Lengauer C (2001). "Chromosome segregation and cancer: cutting through the mystery". Nature Reviews Cancer. 1 (2 ... As previously stated, the disruptions in the chromosome may lead to single chromosome mutations, including deletion, ... a process that ensures that replicated chromosomes are intact before chromosomes are segregated during cell division. In ... This occurs because loss of these genes causes an increase in chromosome fusions, either in an end-to-end manner or through ...
Mary C. Dasso is an American biochemist known for research on chromosome segregation and the discovery of Ran GTPase. She is ... They are now using these systems to examine not only the role of nucleoporins in mitotic chromosome segregation but also how ... Dasso is interested in mechanisms of chromosome segregation. Her group discovered that the Ran GTPase. They showed that Ran ... re-purposed as cells divide to perform transport-independent activities that are essential for accurate chromosome segregation ...
Murray, H; Ferreira, H; Errington, J (Sep 2006). "The bacterial chromosome segregation protein Spo0J spreads along DNA from ... The parABS system is a broadly conserved molecular mechanism for plasmid partitioning and chromosome segregation in bacteria. ... "A spindle-like apparatus guides bacterial chromosome segregation". Nature Cell Biology. 12 (8): 791-8. doi:10.1038/ncb2083. PMC ... Surtees, JA; Funnell, BE (2003). Plasmid and chromosome traffic control: how ParA and ParB drive partition. Current Topics in ...
He generated the first chromosome-wide high resolution maps of proteins involved in chromosome packaging and segregation. He ... "Frank Uhlmann: Mechanism and control of chromosome segregation". The Crick Institute. Archived from the original on 24 May 2015 ... CS1 maint: discouraged parameter (link) Nasmyth, K; Peters, J. M.; Uhlmann, F (2000). "Splitting the chromosome: Cutting the ... "A simple biophysical model emulates budding yeast chromosome condensation". eLife. 4: e05565. doi:10.7554/eLife.05565. PMC ...
... chromosome segregation as well as development and pluripotency. Aberrations in chromatin remodeling proteins are found to be ... DNA repair and chromosome segregation, and therefore exerts tumor-suppressor function. Mutations in such chromatin remodelers ... including chromosome assembly and segregation, DNA replication and repair, embryonic development and pluripotency, and cell- ... Loss of heterozygosity in coding region of p300 (chromosome 22q13) is present in large number of glioblastomas. Further, HATs ...
Chromosome segregation Clastogen Non-disjunction Plante, N. (2003). Molecular toxicology. Taylor & Francis. pp. 63-65. ISBN 978 ... Exposure to fenvalerate raised sex chromosome disomy 1.9-fold and disomy of chromosome 18 by 2.6-fold (Xia et al., 2004). ... and also increased sex chromosome disomy by 1.7-fold and chromosome 18 disomy by 2.2-fold. Humans are exposed to perfluorinated ... An aneugen is a substance that causes a daughter cell to have an abnormal number of chromosomes or aneuploidy. A substance's ...
Chromosome segregation Candida albicans India portal Biology portal Medicine portal "Faculty - JNCASR". www.jncasr.ac.in. 3 ... Essential Components for Chromosome Segregation. Wiley-VCH Verlag GmbH & Co. KGaA. pp. 259-288. doi:10.1002/9783527697274.ch9. ... Sreekumar, Lakshmi; Varshney, Neha; Sanyal, Kaustuv (2017). Chromosome Components Important for Genome Stability in Candida ... "The CENP-A homolog CaCse4p in the pathogenic yeast Candida albicans is a centromere protein essential for chromosome ...
Prasanth SG, Prasanth KV, Stillman B (2002). "Orc6 involved in DNA replication, chromosome segregation, and cytokinesis". ... interfering RNA demonstrated that this protein plays an essential role in coordinating chromosome replication and segregation ...
"Human chromokinesin KIF4A functions in chromosome condensation and segregation". The Journal of Cell Biology. 166 (5): 613-20. ... Chromosome-associated kinesin KIF4A is a protein that in humans is encoded by the KIF4A gene. KIF4A Foundation is a nonprofit ... Chromosome-associated kinesin KIF4A is a protein that in humans is encoded by the KIF4A gene. Kinesins, such as KIF4A, are ... to human chromosome bands Xq13.1 and 5q33.1 by in situ hybridization". Cytogenetics and Cell Genetics. 88 (1-2): 41-2. doi: ...
Dworkin J, Losick R (October 2002). "Does RNA polymerase help drive chromosome segregation in bacteria?". Proceedings of the ... SMC proteins responsible for chromosome condensation in eukaryotic cells. Viral DNA packaging motors inject viral genomic DNA ... Peterson CL (November 1994). "The SMC family: novel motor proteins for chromosome condensation?". Cell. 79 (3): 389-92. doi: ...
Seidman, MM; Levine, AJ; Weintraub, H (1979). "The asymmetric segregation of parental nucleosomes during chromosome replication ... Riley, D; Weintraub, H (1979). "Conservative segregation of parental histones during replication in the presence of ...
Klebig C, Korinth D, Meraldi P (Jun 2009). "Bub1 regulates chromosome segregation in a kinetochore-independent manner". The ... "PP2A is required for centromeric localization of Sgo1 and proper chromosome segregation". Developmental Cell. 10 (5): 575-85. ... The protein is bound to kinetochores and plays a key role in the establishment of the mitotic spindle checkpoint and chromosome ... The protein kinase Bub1 possesses versatile and distinct functions during the cell cycle, mainly in the SAC and chromosome ...
It is involved in chromosome segregation during cell division. It also has a role in the orientation of microtubules to form ... It remains part of the kinetochore through early anaphase (the chromosome-dividing phase). In late anaphase, CENPF localises to ... 2005). "FoxM1 is required for execution of the mitotic programme and chromosome stability". Nat. Cell Biol. 7 (2): 126-36. doi: ... Kobayashi M, Hanai R (2001). "M phase-specific association of human topoisomerase IIIbeta with chromosomes". Biochem. Biophys. ...
"PKM2 regulates chromosome segregation and mitosis progression of tumor cells". Molecular Cell. 53 (1): 75-87. doi:10.1016/j. ... the spindle assembly protein Bub3 to regulate chromosome segregation and mitotic checkpoint in metaphase, and myosin light ...
... the segregation of chromosomes continue and both the phases of meiotic segregations take place on prolonged meiosis I spindle. ... Higuchi, T; Uhlmann, F (2005). "Stabilization of microtubule dynamics at anaphase onset promotes chromosome segregation". ... "The Cdc14 phosphatase and the FEAR network control meiotic spindle disassembly and chromosome segregation". Developmental Cell ... The chromosomes also segregate abnormally. The abnormality arises due to delay in dissembling of spindle during Anaphase I. ...
Falconer, Ester; Lansdorp, Peter M. (August 2013). "Strand-seq: A unifying tool for studies of chromosome segregation". ... Pulse-chase experiments have been used for determining the segregation patterns of chromosomes in addition to studying other ... aneuploid chromosomes and modes of sister chromatid segregation. It can also aid in assembling early-build genomes and ... "The Majority of Multipotent Epidermal Stem Cells Do Not Protect Their Genome by Asymmetrical Chromosome Segregation". Stem ...
Then the metaphase spindle assembles and chromosome segregation can occur. The transcription of Sic1 starts during telophase, ...
This protein acts to regulate microtubule dynamics in cells and is important for anaphase chromosome segregation and may be ... "Mitotic Centromere-associated Kinesin Is Important for Anaphase Chromosome Segregation". J. Cell Biol. 142 (3): 787-801. doi: ... proteins of this family are microtubule-dependent molecular motors that transport organelles within cells and move chromosomes ...
"Deregulated human Cdc14A phosphatase disrupts centrosome separation and chromosome segregation". Nature Cell Biology. 4 (4): ...
"Defective chromosome segregation and telomere dysfunction in aggressive Wilms' tumors". Clinical Cancer Research. 13 (22 Pt 1 ... This latter gene is found on short arm of chromosome 3 (3p22.1). Most cases do not have mutations in any of these genes. An ... H19 is a long noncoding RNA located on the short arm of chromosome 11 (11p15.5). Play media The majority of people with Wilms' ... Tumor-specific loss-of-heterozygosity (LOH) for chromosomes 1p and 16q identifies a subset of Wilms' tumor patients who have a ...
Higuchi T, Uhlmann F (January 2005). "Stabilization of microtubule dynamics at anaphase onset promotes chromosome segregation ... to human chromosome band 20q11.2 by in situ hybridization". Cytogenetics and Cell Genetics. 84 (3-4): 182-3. doi:10.1159/ ... "Chromosome-induced microtubule assembly mediated by TPX2 is required for spindle formation in HeLa cells". Nature Cell Biology ... "Chromosome-induced microtubule assembly mediated by TPX2 is required for spindle formation in HeLa cells". Nature Cell Biology ...
... and not sex segregation".[1]:229 [2][7][8] "Segregation" is a term that has long been associated with racial segregation in the ... chromosomes and anatomy' at birth.[32] ... Sex-separation in public toilets (also called sex segregation ... Some scholars have tied toilet sex-separation to segregation based on race discrimination in the US.[67] Advocates of this view ... Ancient evidence, including art-work, confirms widespread use of sex-separation (or sex segregation), especially in multi-use ...
... separate sexes and sex chromosomes, segregation distortion and repetitive DNA. ...
... in males with normal chromosomes because they have only one X chromosome and few of the same genes are on the Y chromosome. ... Gupta, R.S.; Chan, D.H.Y.; Siminovitch, L. (1978). "Evidence obtained by segregation analysis for functional hemizygosity at ... A chromosome in a diploid organism is hemizygous when only one copy is present.[2] The cell or organism is called a hemizygote ... Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each ...
Deletion in the 22q11.2 region of chromosome 22 has been associated with schizophrenia and autism.[22][23] Schizophrenia and ... The disease is caused by a defect in a single gene on chromosome 12 that codes for enzyme phenylalanine hydroxylase , that ... and can be caused by any of a large number of mutations in the single gene on chromosome 12 that codes for the enzyme ... especially if the gene is located on an autosomal chromosome.[14] ...
condensed chromosome. • nuclear chromosome, telomeric region. • nucleus. • nuclear chromatin. • lateral element. • cytosol. • ... Crickard JB, Kaniecki K, Kwon Y, Sung P, Greene EC (2018). "Spontaneous self-segregation of Rad51 and Dmc1 DNA recombinases ... nuclear chromosome. • mitochondrial matrix. • nucleolus. • mitochondrion. • perinuclear region of cytoplasm. • chromatin. • ... condensed nuclear chromosome. • macromolecular complex. Biological process. • regulation of protein phosphorylation. • strand ...
選擇可以作用在基因而非個體的層級,即使降低個體的適應度,自私DNA仍然可以演化,造成基因組內部衝突。例子包括跳躍子、減數分裂驅動者(meiotic drivers)、殺手X染色體(killer X chromosomes)、自私粒線體(selfish ... segregation load)[9]。 ... Thomas Jr, C. A. The genetic organization of chromosomes (PDF) ... Crosland, M.W.J., Crozier, R.H. Myrmecia pilosula, an ant with only one pair of chromosomes. Science. 1986, 231 (4743):
... called 46/47 XY/XXY mosaic wherein some of the patient's cells contain XY chromosomes, and some contain XXY chromosomes. The 46 ... "Somatic crossing-over and segregation in Drosophila melanogaster". Genetics 21, 625-730. ... where a fly possessing two X chromosomes is a female and a fly possessing a single X chromosome is a sterile male, a loss of an ... This may be caused by a nondisjunction event in an early mitosis, resulting in a loss of a chromosome from some trisomic cells. ...
"Variation in crossover frequencies perturb crossover assurance without affecting meiotic chromosome segregation in ... "MutS homolog 4 localization to meiotic chromosomes is required for chromosome pairing during meiosis in male and female mice". ... "hMSH4-hMSH5 recognizes Holliday Junctions and forms a meiosis-specific sliding clamp that embraces homologous chromosomes". ...
"A Y Chromosome Census of the British Isles" (PDF).. *^ Härke, Heinrich; Thomas, Mark G; Stumpf, Michael P H. "Integration ... In 1253 the Statute of Jewry, reinforced physical segregation and demanded a previously notional requirement to wear square ... "Y Chromosome Evidence for Anglo-Saxon Mass Migration".. *^ " ...
The physical basis of the independent assortment of chromosomes is the random orientation of each bivalent chromosome along the ... Law of Segregation of genes (the "First Law")[edit]. Figure 1 Dominant and recessive phenotypes.. (1) Parental generation.. (2 ... In independent assortment, the chromosomes that result are randomly sorted from all possible maternal and paternal chromosomes ... The zygote will normally end up with 23 chromosomes pairs, but the origin of any particular chromosome will be randomly ...
In Gammaproteobacteria, adenine methylation provides signals for DNA replication, chromosome segregation, mismatch repair, ... Methylation of cytosines can also persist from the germ line of one of the parents into the zygote, marking the chromosome as ... In 2008, a consensus definition of the epigenetic trait, "stably heritable phenotype resulting from changes in a chromosome ... Specific epigenetic processes include paramutation, bookmarking, imprinting, gene silencing, X chromosome inactivation, ...
His story lines have focused on the segregation of those with disabilities in the UK in the 1950s, and also romantic ... "A gene for ataxic cerebral palsy maps to chromosome 9p12-q12". European Journal of Human Genetics. 8 (4): 267-272. doi:10.1038/ ...
Male birds have two Z chromosomes (ZZ), and female birds have a W chromosome and a Z chromosome (WZ).[62] ... "Variation in Altitudinal Migration, Winter Segregation, and Site Tenacity in two subspecies of Dark-eyed Juncos in the ... Chromosomes. Birds have two sexes: either female or male. The sex of birds is determined by the Z and W sex chromosomes, rather ... than by the X and Y chromosomes present in mammals. ...
During meiosis, chromosomes assort randomly into gametes, such that the segregation of alleles of one gene is independent of ... when two genes are located on different chromosomes or when they are widely separated on the same chromosome. This is a ... Markers on different chromosomes are perfectly unlinked. Genetic linkage is the most prominent exception to Gregor Mendel's Law ... Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the ...
... s have 21 pairs of chromosomes (2n=42).[106] The genome of live whales can be examined by recovering shed skin.[107] ... The main driving force for the sexual segregation of adult sperm whales is scramble competition for mesopelagic squid.[168] ...
In evolution, this chromosome has lost most of its content and also most of its genes, while the X chromosome is similar to the ... These observations of discrete inheritance and the segregation of alleles are collectively known as Mendel's first law or the ... During crossover, chromosomes exchange stretches of DNA, effectively shuffling the gene alleles between the chromosomes.[59] ... Chromosomes are copied, condensed, and organized. Then, as the cell divides, chromosome copies separate into the daughter cells ...
Jackson, John P. (2005). Science for Segregation: Race, Law, and the Case against Brown v. Board of Education. NYU Press. ISBN ... When looking at the Y-chromosome there are three large haplogroups which account for most of Europe's patrilineal descent.[120] ... November 2000), "The genetic legacy of Paleolithic Homo sapiens sapiens in extant Europeans: a Y chromosome perspective", ...
This incorrect segregation of chromosomes may result from hypomethylation of repeat sequences present in pericentromeric DNA, ... Sex chromosomes contribute to the majority of chromosome loss events with increasing age. In females, the X chromosome can ... Micronucleus is the name given to the small nucleus that forms whenever a chromosome or a fragment of a chromosome is not ... Micronuclei originating from chromosome loss events and acentric chromosome fragments can be distinguished using pancentromeric ...
In gene conversion, a section of genetic material is copied from one chromosome to another, without the donating chromosome ... Achiasmatic chromosomal segregation is well documented in male Drosophila melanogaster. Heterochiasmy occurs when recombination ... This process appears to be an adaptation for repairing DNA damages in the recipient chromosome by HRR.[11] Transformation may ... Indicated on the right side is a "crossover" (CO) type, where the flanking regions of the chromosomes are exchanged, and on the ...
BRCA 1 has the cytogenetic location 17q21 or the q arm of Chromosome 17 at position 21. BRCA 2 has the cytogenetic location ... "After BRCA1 and BRCA2-what next? Multifactorial segregation analyses of three-generation, population-based Australian families ... The BRCA genes are tumour suppressor genes pictured here on their respective chromosomes. ... but lack of BRCA1 function seems to lead to non-functional X-chromosome inactivation. Not all mutations are high-risk; some ...
... not considering that crossover events can take place at most points along each chromosome. The X and Y chromosomes undergo no ... Meiosis results in a random segregation of the genes that each parent contributes. Each parent organism is usually identical ... In humans, (2²²)² = 17.6x1012 chromosomally different zygotes are possible for the non-sex chromosomes, even assuming no ... haploid number of chromosomes)[12] - a growing pollen tube therefore contains three separate nuclei, two sperm and one tube.[13 ...
chromosome segregation. • protein K6-linked ubiquitination. • intrinsic apoptotic signaling pathway in response to DNA damage. ... condensed chromosome. • cytoplasm. • chromosome. • cell nucleus. • lateral element. • macromolecular complex. • ... condensed nuclear chromosome. • gamma-tubulin ring complex. • BRCA1-A complex. • ubiquitin ligase complex. • plasma membrane. • ... a b US patent 5837492, Tavtigian SV, Kamb A, Simard J, Couch F, Rommens JM, Weber BL, "Chromosome 13-linked breast cancer ...
... segregation of ice occurs in intercellular spaces.[62] This may or may not be lethal, depending on the hardiness of the tissue ... and examination of chromosomes in maize allowed Barbara McClintock to demonstrate their connection to inherited traits.[102] ...
... proper chromosome segregation and cytokinesis.. Diagnosis[edit]. Since primordial dwarfism disorders are extremely rare, ...
Crossing over is essential for the normal segregation of chromosomes during meiosis.[citation needed] Crossing over also ... So, when the chromosomes go on to meiosis II and separate, some of the daughter cells receive daughter chromosomes with ... this mutant gave rise to spore viability patterns suggesting that segregation of non-exchange chromosomes occurred efficiently ... "Variation in crossover frequencies perturb crossover assurance without affecting meiotic chromosome segregation in ...
... chromosome segregation, and cytokinesis. Eukaryotic cell division either involves mitosis or a more complex process called ... There are two distinct sex chromosomes, the X chromosome and the Y chromosome. A diploid human cell has 23 chromosomes from ... In each double chromosome there are two copies of that chromosome's DNA molecule. During mitosis the double chromosomes are ... Information from the chromosome 2 DNA gained from one parent (red) will transfer over to the chromosome 2 DNA molecule that was ...
The final chromosomes in the two human gametes are called sex chromosomes because of their role in sex determination. Ova ... sex segregation, gender equality, marriage, abortion, homosexuality) ... About half of spermatozoa also have this same X chromosome, the rest have a Y-chromosome. At fertilization the gametes fuse to ... In fact, there are typically many of these "books", called chromosomes. Human gametes usually have 23 chromosomes, 22 of which ...
Vegetative segregation[edit]. Vegetative segregation, the random partitioning of cytoplasm, is a distinguishable characteristic ... because plastid genes are usually on a single chromosome and recombination is limited by uniparental inheritance.[4] ... It refers to the selective segregation of certain genotypes in mitochondrial DNA that allows the favoured genotype to thrive. ... Although a single mutational event might be rare in its generation, repeated mitotic segregation and clonal expansion can ...
After the first chromosome segregation in meiosis I is complete, there is further chromosome segregation during the second ... Both proper initial segregation of chromosomes in prophase I and the next chromosome segregation during equational division in ... Chromosome segregation also occurs in prokaryotes. However, in contrast to eukaryotic chromosome segregation, replication and ... Improper chromosome segregation can result in aneuploid gametes having either too few or too many chromosomes. The second stage ...
CSE1L chromosome segregation 1 like [Homo sapiens] CSE1L chromosome segregation 1 like [Homo sapiens]. Gene ID:1434 ... CSE1 chromosome segregation 1-like. cellular apoptosis susceptibility protein. chromosome segregation 1-like protein. ... chromosome segregation 1 likeprovided by HGNC. Primary source. HGNC:HGNC:2431 See related. Ensembl:ENSG00000124207 MIM:601342 ... CSE1L chromosome segregation 1 like [ Homo sapiens (human) ] Gene ID: 1434, updated on 3-May-2020 ...
Caulobacter chromosome segregation is an ordered multistep process. Proc. Natl. Acad. Sci. U.S.A. 107, 14194-14198 (2010).. ... The kinetochore and the origin of eukaryotic chromosome segregation. Mark C. Field. *. aSchool of Life Sciences, University of ... Poring over chromosomes: Mitotic nuclear pore complex segregation. Curr. Opin. Cell Biol. 58, 42-49 (2019).. ... The kinetochore and the origin of eukaryotic chromosome segregation Message Subject (Your Name) has sent you a message from ...
The Saccharomyces Genome Database (SGD) provides comprehensive integrated biological information for the budding yeast Saccharomyces cerevisiae.
In most animal species, chromosome segregation during female meiosis occurs on spindles assembled in the absence of the major ... Acentrosomal spindle assembly and chromosome segregation during oocyte meiosis.. Dumont J1, Desai A. ... During anaphase I, dissolution of chromosome arm cohesion leads to reductional segregation of homologs. Sister chromatids are ... The nature of the link between microtubules and chromosomes, and whether microtubule assembly and/or sliding promote chromosome ...
Knockdown of Gie in Drosophila cells also blocked normal sister chromosome segregation but did not block the progression of ... Named Gie1 and Gie2 (GTPases indispensible for equal segregation of chromosomes), the new members share about 30% amino acid ... Novel small GTPase subfamily capable of associating with tubulin is required for chromosome segregation. J. Cell Sci. 117, 4705 ... may localize to the spindle mid-zone and mid-body to control chromosome segregation. ...
Abnormal segregation can cause cell death or diseases like Down syndrome and cancer. Filamentous spindle fibers must bind to ... For the spindle fiber to be correctly joined, the chromosome must have heterochromatin. However, the mechanism for forming this ... chromosomes need to be evenly segregated. This equal distribution is important to accurately pass genetic information to the ... The chromosome centromere is an essential area for chromosome movement and accurate segregation in which a kinetochore ...
Home Blog Entry New insight into chromosome segregation: Centromere-independent kinetochore assembly ... New insight into chromosome segregation: Centromere-independent kinetochore assembly. April 28, 2011. ... provides fascinating new insight into the complex of proteins that orchestrates the proper segregation of human chromosomes ... Duplicated chromosomes are attached together at a region called the centromere. The centromere plays an important role in the ...
Non-Mendelian Segregation of Sex Chromosomes in Heterospecific Drosophila Males Message Subject (Your Name) has forwarded a ... Non-Mendelian Segregation of Sex Chromosomes in Heterospecific Drosophila Males. Emmanouil T. Dermitzakis, John P. Masly, Heidi ... Non-Mendelian Segregation of Sex Chromosomes in Heterospecific Drosophila Males. Emmanouil T. Dermitzakis, John P. Masly, Heidi ... Non-Mendelian Segregation of Sex Chromosomes in Heterospecific Drosophila Males. Emmanouil T. Dermitzakis, John P. Masly, Heidi ...
Chromosome Segregation; Centrosomes and Centrioles; Ploidy, Chromosome Segregation Errors, and Disease; Asymmetric Cell ... Organizing Chromosomes during Segregation. Noncanonical Biogenesis of Centrioles and Basal Bodies. Catarina Nabais, Sónia Gomes ... Impact of Centrosome Aberrations on Chromosome Segregation and Tissue Architecture in Cancer. Erich A. Nigg, Dominik Schnerch, ... The 82nd Cold Spring Harbor Symposium focused on Chromosome Segregation & Structure and addressed the enormous progress in our ...
Efficient chromosome segregation requires the co-ordination of several cellular processes; some of which involve gross ... Chromosome segregation is an essential feature of the eukaryotic cell cycle. ... Chromosome segregation is an essential feature of the eukaryotic cell cycle. Efficient chromosome segregation requires the co- ... The role of SUMO in chromosome segregation Chromosoma. 2007 Feb;116(1):15-20. doi: 10.1007/s00412-006-0079-z. Epub 2006 Oct 10 ...
... the link between chromosome and kinetochore would fail, as would chromosome segregation and cell division. ... Whitehead Institute researchers have determined the organization of a protein complex that is critical during chromosome ... segregation. Without the solid foundation supplied by this complex, which is called the Constitutive Centromere-Associated ... as would chromosome segregation and cell division. "The CCAN forms the critical connection between the DNA and the segregation ...
Non-random segregation of chromosomes is a deviation from the usual distribution of chromosomes during meiosis, that is, during ... The mitotic assymetry with non-random segregation of chromosomes arises from unequal partitioning of chromosomes according to ... In such cases, one does not speak of X and Y chromosomes, but of Z and W chromosomes. Males have two Z chromosomes (ZZ), ... There are two different X chromosomes and no Y chromosome (X1X20), and in meiosis I both X chromosomes are assigned to the same ...
Our results are consistent with a role for ObgE in chromosome partitioning, with defects in chromosome segregation observed ... A reasonable hypothesis is that ObgE is required to license chromosome segregation and, in its absence, chromosomes are ... The mechanism of bacterial chromosome segregation is still mysterious, although the demonstration of segregation defects ... loss of sister cohesion triggers global chromosome movement and mediates chromosome segregation. Cell 121: 899-911. *CrossRef ...
How do these chromosome segregation defects account for the observed patterns of NPC aneuploidy? Lagging chromosomes and ... B-E, Chromosome segregation defects and consequently aneuploidy can result from lagging chromosomes (B), supernumerary ... Chromosome segregation defects can lead to aneuploidy. A, During normal mitosis, metaphase chromosomes establish bipolar ... The euploid chromosome number for Mus musculus is 40. The chromosome spread has only one copy of chromosomes 3 and 10 (38, XY ...
... Author(s). ... "A Developmentally Regulated Translational Control Pathway Establishes the Meiotic Chromosome Segregation Pattern." Genes & ... including the critical determinant of the meiotic chromosome segregation pattern CLB3. We further show that Ime2 mediates ... elucidate a novel developmentally regulated translational control pathway that establishes the meiotic chromosome segregation ...
In the majority of bacterial species, faithful chromosome segregation is… ... Proper chromosome segregation during cell division is essential in all domains of life. ... Proper chromosome segregation during cell division is essential in all domains of life. In the majority of bacterial species, ... Additionally, we discuss outstanding questions and challenges in understanding bacterial chromosome segregation. ...
RED1: a yeast gene required for the segregation of chromosomes during the reductional division of meiosis. B Rockmill and G S ... RED1: a yeast gene required for the segregation of chromosomes during the reductional division of meiosis ... Expression and DNA sequence of RED1, a gene required for meiosis I chromosome segregation in yeast ... RED1: a yeast gene required for the segregation of chromosomes during the reductional division of meiosis ...
... Nat Rev Cancer. 2001 Nov;1(2):109-17. doi: 10.1038/35101065. ... Chromosome Aberrations * Chromosome Segregation / drug effects * Chromosome Segregation / genetics * Chromosome Segregation / ...
However, when crossed to the wild type, hybrid progeny suffered from extensive mis-segregation. Genotypes include simple ... aneuploids, novel genetic rearrangements, and in extreme cases haploids where all the chromosomes from one parent are lost. ...
Genetic assays of meiotic chromosome segregation. To test whether dtopors mutations caused sex chromosome and fourth chromosome ... Nuclear Structure and Chromosome Segregation in Drosophila Male Meiosis Depend on the Ubiquitin Ligase dTopors. Maiko Matsui, ... At anaphase/telophase I, chromosome segregation appeared normal in dtopors f05115/+; mnmZ5578/+ (n = 30). In dtopors f05115/+; ... Nuclear Structure and Chromosome Segregation in Drosophila Male Meiosis Depend on the Ubiquitin Ligase dTopors. Maiko Matsui, ...
However, only a few studies have examined the relationship between chromosome segregation errors during early cleavage and ... These results suggest that early chromosome segregation error causing micronuclei formation affects ploidy and development to ... aneuploidy resulting from chromosome segregation error is considered responsible for pregnancy loss. ... We showed that some embryos exhibiting early chromosomal segregation error and formation of micronuclei retained their ...
Hence, the segregation of the genome is coordinated in time and space.. To study chromosome segregation we implement a multi- ... generating offspring with a correct number of chromosomes. Errors made during chromosome segregation e.g., due to a lack or ... As chromosome segregation and the proteins involved are evolutionary conserved we study them in the yeast Saccharomyces ... To identify new proteins involved in chromosome segregation we perform protein affinity purifications and yeast two-hybrid ...
This protocol describes an easy and convenient method to label and visualize live chromosomes in mitotic cells using Histone2B- ... Cell cycle control checkpoints that ensure accurate chromosome segregation prevent aneuploidy and cell transformation 1,2,3. In ... Live Cell Imaging of Chromosome Segregation During Mitosis. Prajakta Varadkar1, Kazuyo Takeda2, Brenton McCright1 ... Varadkar, P., Takeda, K., McCright, B. Live Cell Imaging of Chromosome Segregation During Mitosis. J. Vis. Exp. (133), e57389, ...
Laboratory for Chromosome Segregation Website , RIKEN Center for Biosystems Dynamics Research. You are encouraged to contact to ... The Laboratory for Chromosome Segregation is seeking to recruit a motivated research scientist who carries out researches ... Laboratory for Chromosome Segregation. RIKEN Center for Biosystems Dynamics Research. (Team Leader: Tomoya Kitajima) ... For more information about researches in the Laboratory for Chromosome Segregation, please refer to the following website:. ...
Cortical CDC42 depends on polarization directed by chromosomes, which are positioned near the cortex to allow the asymmetric ... from the cell cortex regulated microtubule tyrosination to induce spindle asymmetry and that non-Mendelian segregation depended ...
To address this question, we discuss how environmental conditions affect chromosome segregation and how segregation proteins ... To address this question, we discuss how environmental conditions affect chromosome segregation and how segregation proteins ... This notion provokes the question of whether chromosome segregation can be regarded as a regulatory stage of the cell cycle. ... This notion provokes the question of whether chromosome segregation can be regarded as a regulatory stage of the cell cycle. ...
... as more is known about the basic mechanisms of cell cycle regulation and chromosome segregation, certain lagging chromosome ... Mitotic Centromere-associated Kinesin Is Important for Anaphase Chromosome Segregation. Todd Maney, Andrew W. Hunter, Mike ... Effect of endogenous MCAK depletion on chromosome segregation. Mitotic cells triple-labeled with anti-MCAK (A, D, G, J, M); ... 1994) Video time-lapse study of mitosis in binucleate V79 cells: chromosome segregation and cleavage. Mutagenesis 9:117-123, ...
Cdk5rap2 regulates centrosome function and chromosome segregation in neuronal progenitors Message Subject (Your Name) has sent ... Cdk5rap2 regulates centrosome function and chromosome segregation in neuronal progenitors. Sofia B. Lizarraga, Steven P. ... Cdk5rap2 regulates centrosome function and chromosome segregation in neuronal progenitors. Sofia B. Lizarraga, Steven P. ... Cdk5rap2 regulates centrosome function and chromosome segregation in neuronal progenitors. Sofia B. Lizarraga, Steven P. ...
top-2(it7ts) chromosome-segregation defects are not dependent on SPO-11-induced DSBs. Homologous chromosome segregation during ... and the meiotic division zone analyzed for chromosome-segregation defects. Meiotic chromosome-segregation abnormalities in germ ... 1993 Segregation of holocentric chromosomes at meiosis in the nematode, Caenorhabditis elegans. Chromosome Res. 1: 15-26. ... The number of germ lines with chromosome-segregation defects at 24°: spo-11(ok79)/nT1; top-2(it7ts), 16 of 17; spo-11(ok79); ...
  • This segregation process occurs during both mitosis and meiosis. (wikipedia.org)
  • Chromosome segregation occurs at two separate stages during meiosis called anaphase I and anaphase II (see meiosis diagram). (wikipedia.org)
  • During the phase of meiosis labeled "interphase s" in the meiosis diagram there is a round of DNA replication, so that each of the chromosomes initially present is now composed of two copies called chromatids. (wikipedia.org)
  • These chromosomes (paired chromatids) then pair with the homologous chromosome (also paired chromatids) present in the same nucleus (see prophase I in the meiosis diagram). (wikipedia.org)
  • Following recombination, chromosome segregation occurs as indicated by the stages metaphase I and anaphase I in the meiosis diagram. (wikipedia.org)
  • The second stage at which segregation occurs during meiosis is prophase II (see meiosis diagram). (wikipedia.org)
  • Thus the two chromatids comprising each chromosome separate into different nuclei, so that each nucleus gets a single set of chromatids (now called chromosomes) and each nucleus becomes included in a haploid gamete (see stages following prophase II in the meiosis diagram). (wikipedia.org)
  • After the first chromosome segregation in meiosis I is complete, there is further chromosome segregation during the second equational division of meiosis II. (wikipedia.org)
  • Both proper initial segregation of chromosomes in prophase I and the next chromosome segregation during equational division in meiosis II are required to generate gametes with the correct number of chromosomes. (wikipedia.org)
  • Acentrosomal spindle assembly and chromosome segregation during oocyte meiosis. (nih.gov)
  • In most animal species, chromosome segregation during female meiosis occurs on spindles assembled in the absence of the major microtubule-organizing center, the centrosome. (nih.gov)
  • Here, we review recent work on acentrosomal spindle formation and chromosome alignment/separation during oocyte meiosis in different animal models. (nih.gov)
  • Non-random segregation of chromosomes is a deviation from the usual distribution of chromosomes during meiosis, that is, during segregation of the genome among gametes. (wikipedia.org)
  • This can be due to non-random segregation during meiosis, but also to processes after meiosis that reduce the transmission of the homologous chromosome. (wikipedia.org)
  • According to the chromosome theory of inheritance formulated by Theodor Boveri in 1904, homologous chromosomes were expected to be randomly distributed among the daughter nuclei during meiosis. (wikipedia.org)
  • It turned out that meiosis I is inequal, i.e. results in two unequal-sized cells, and the X chromosome always ends up in the larger daughter cell. (wikipedia.org)
  • There are two different X chromosomes and no Y chromosome (X1X20), and in meiosis I both X chromosomes are assigned to the same daughter nucleus. (wikipedia.org)
  • Ime2 coordinates translational activation of a cluster of genes at the meiosis I-meiosis II transition, including the critical determinant of the meiotic chromosome segregation pattern CLB3. (mit.edu)
  • In contrast to mitosis, meiosis has two rounds of chromosome segregation following one round of DNA replication. (genetics.org)
  • Unlike mitosis, which has a single round of DNA replication followed by one round of chromosome segregation, meiosis consists of a single round of DNA replication followed by two rounds of chromosome segregation. (genetics.org)
  • Meiosis-specific Top2 RNAi in Drosophila results in sterility due to defects in homolog segregation ( Hughes and Hawley 2014 ). (genetics.org)
  • Fixation of Rb fusions can be explained by meiotic drive: biased chromosome segregation during female meiosis. (upenn.edu)
  • In meiosis I, homologous chromosomes segregate, while sister chromatids remain together. (elifesciences.org)
  • Here we show that preventing microtubule-kinetochore interactions during premeiotic S phase and prophase I is essential for establishing the meiosis I chromosome segregation pattern. (elifesciences.org)
  • Premature interactions of kinetochores with microtubules transform meiosis I into a mitosis-like division by disrupting two key meiosis I events: coorientation of sister kinetochores and protection of centromeric cohesin removal from chromosomes. (elifesciences.org)
  • We propose that inhibition of microtubule-kinetochore interactions during premeiotic S phase and prophase I is central to establishing the unique meiosis I chromosome segregation pattern. (elifesciences.org)
  • During meiosis I, homologous chromosomes are separated. (elifesciences.org)
  • Subsequently, during meiosis II, the sister chromatids separate to produce a total of four products, each with half the number of chromosomes as the original cell. (elifesciences.org)
  • During meiosis I, on the other hand, they attach to kinetochores in a manner so the homologous chromosomes are pulled apart. (elifesciences.org)
  • These results demonstrate that preventing premature microtubule-kinetochore interactions is essential for establishing a meiosis I-specific chromosome architecture, and they also provide fresh insights into how the molecular machinery that is responsible for mitotic chromosome segregation can be modulated to achieve meiosis. (elifesciences.org)
  • In the absence of the checkpoint, the frequency of meiosis I missegregation increased with increasing chromosome length, reaching 19% for the longest chromosome. (sciencemag.org)
  • Spindle checkpoint mutants reduce the accuracy of chromosome segregation in meiosis I much more than that in meiosis II, suggesting that checkpoint defects may contribute to Down syndrome. (sciencemag.org)
  • In the course of maturation, they divide their set of chromosomes in half via a specialized cell division termed meiosis. (mpg.de)
  • Actin protects mammalian oocytes from defects during chromosome segregation," points out Melina Schuh, Director of the Department of Meiosis at the institute. (mpg.de)
  • We observed a dramatic loss of spore viability in fission yeast lacking all four TLSPs, which is accompanied by disruptions in chromosome segregation during meiosis I and II. (caltech.edu)
  • During meiosis, diploid organisms reduce their chromosome number by half to generate haploid gametes. (prolekare.cz)
  • However, these anaphase I bridges were often able to resolve in a LEM-3 nuclease dependent manner, and chromosome tethers that persisted were frequently resolved during Meiosis II by a second mechanism that preferentially segregates the tethered sister chromatid into the polar body. (prolekare.cz)
  • Altogether these findings demonstrate that excess interfering crossovers can severely impact chromosome patterning and segregation, highlighting the importance of limiting the number of recombination events between homologous chromosomes for the proper execution of meiosis. (prolekare.cz)
  • 10. Kaitna S, Pasierbek P, Jantsch M, Loidl J, Glotzer M. The aurora B kinase AIR-2 regulates kinetochores during mitosis and is required for separation of homologous chromosomes during meiosis. (prolekare.cz)
  • Homologous recombination is essential for crossover (CO) formation and accurate chromosome segregation during meiosis. (bionity.com)
  • Cohesin complexes maintain sister chromatid cohesion to ensure proper chromosome segregation during mitosis and meiosis. (plantcell.org)
  • Chromosomes and genes share all of the following characteristics except that Possible Answers A. they both undergo segregation during meiosis. (coursehero.com)
  • A. they both undergo segregation during meiosis. (coursehero.com)
  • A novel chromosome segregation mechanism during female meiosis. (escholarship.org)
  • Accurate chromosome segregation during meiosis depends on protein linkages (cohesion) that hold sister chromatids together. (prolekare.cz)
  • Because the majority of human oocytes remain arrested for decades, the continued physical association of recombinant homologs and their accurate segregation during meiosis I demands that cohesion along the arms of sister chromatids remain intact during this extended timeframe. (prolekare.cz)
  • Chromosome segregation errors during female meiosis are the leading cause of miscarriages and birth defects in humans [8] . (prolekare.cz)
  • https://doi.org/10.1083/jcb.202005179 ) show that kinetochore proteins KNL-1 and KNL-3 are required for early stages of anaphase during female meiosis, suggesting a new kinetochore-based model of chromosome segregation. (rupress.org)
  • Meiosis consists of two consecutive chromosome segregation events preceded by a single round of DNA replication. (rupress.org)
  • Homologous chromosomes are separated in meiosis I, which is followed by sister chromatid separation in meiosis II to produce haploid gametes. (rupress.org)
  • In many organisms, including mammals, oocytes lack centrosomes, and it has been of great interest to clarify the mechanisms used to ensure chromosomes are properly segregated during female meiosis ( 5 , 6 ). (rupress.org)
  • The spindle assembly checkpoint (SAC) monitors attachment to microtubules and tension on chromosomes in mitosis and meiosis. (uni-bielefeld.de)
  • Human female meiosis revised: new insights into the mechanisms of chromosome segregation and aneuploidies from advanced genomics and time-lapse imaging. (scienceopen.com)
  • Rescue of a single yeast artificial chromosome from a cotransformation event utilizing segregation at meiosis. (ox.ac.uk)
  • We present a simple method to rescue the required YAC that utilizes the segregation of chromosomes at meiosis. (ox.ac.uk)
  • Modifications of centromeric cohesin for meiosis specific chromosome segregation]. (ox.ac.uk)
  • In both meiosis and mitosis, accurate chromosome segregation relies on the correct orientation of sister chromatids during metaphase, which ensures bipolar spindle attachment. (ed.ac.uk)
  • In biology , meiosis is the process by which the number of chromosomes in a cell nucleus is halved during the formation of germ cells ( eggs and sperm ). (newworldencyclopedia.org)
  • In meiosis, the diploid cell's genome, which is composed of ordered structures of coiled DNA called chromosomes, is replicated once and separated twice, producing four haploid cells, with each containing half (one set) of the original cell's chromosomes. (newworldencyclopedia.org)
  • Meiosis uses many biochemical processes that are similar to those used in mitosis in order to distribute chromosomes among the resulting cells, but the outcome is very different. (newworldencyclopedia.org)
  • The significance of meiosis for reproduction and inheritance , however, was not described until 1890 by German biologist August Weismann (1834-1914), who noted that two cell divisions were necessary to transform one diploid cell into four haploid cells if the number of chromosomes had to be maintained. (newworldencyclopedia.org)
  • In 1911, American geneticist Thomas Hunt Morgan (1866-1945) observed crossover (an exchange of material between two chromosomes) in Drosophila melanogaster meiosis and provided the first true genetic interpretation of meiosis. (newworldencyclopedia.org)
  • Chromosome segregation is the process in eukaryotes by which two sister chromatids formed as a consequence of DNA replication, or paired homologous chromosomes, separate from each other and migrate to opposite poles of the nucleus. (wikipedia.org)
  • In a diploid cell there are two sets of homologous chromosomes of different parental origin (e.g. a paternal and a maternal set). (wikipedia.org)
  • The process of alignment of paired homologous chromosomes is called synapsis (see Synapsis). (wikipedia.org)
  • Meiotic chromosomal crossover (CO) recombination facilitates the proper segregation of homologous chromosomes. (wikipedia.org)
  • Together with cohesion linkage between sister chromatids, CO recombination may help ensure the orderly segregation of the paired homologous chromosomes to opposite poles. (wikipedia.org)
  • Recombined homologous chromosomes are held together by sister chromatid cohesion after exchange of genetic material during meiotic recombination at the chiasma. (nih.gov)
  • While usually according to the 2nd Mendelian rule ("Law of Segregation of genes") homologous chromosomes are randomly distributed among daughter nuclei, there are various modes deviating from this in numerous organisms that are "normal" in the relevant taxa. (wikipedia.org)
  • It also happens that non-homologous chromosomes segregate in a coordinated manner. (wikipedia.org)
  • The separation of homologous chromosomes or sister chromatids relies on them being pulled apart by microtubules. (elifesciences.org)
  • This process depends on the repair of double strand DNA breaks as crossover recombination events between homologous chromosomes, which hold homologs together to ensure their proper segregation to opposite spindle poles during the first meiotic division. (prolekare.cz)
  • It was determined that the suppression of the TRF2 expression violates the development of a compact chromocenter and the correct approach of homologous chromosomes (in germinative and somatic cells). (deepdyve.com)
  • By maintaining chiasmata, arm cohesion promotes proper orientation and microtubule attachments of homologous chromosomes on the metaphase I spindle and is therefore crucial for accurate segregation of homologs during the first meiotic division. (prolekare.cz)
  • However, because microtubules emanating from the spindle poles are not required to separate the homologous chromosomes but microtubules between the separating chromosomes are ( 8 ), this model is unlikely, at least as an explanation for mid-/late-anaphase movement. (rupress.org)
  • End-on contact with a kinetochore results in `capture' of a chromosome and stabilization of the microtubule to form a kinetochore fiber (orange). (nih.gov)
  • Kinetochore fibers are periodically destabilized and re-established to maintain oscillating chromosomes at the spindle equator during the extended prometaphase. (nih.gov)
  • The chromosome centromere is an essential area for chromosome movement and accurate segregation in which a kinetochore structure forms a connection to a spindle fiber. (eurekalert.org)
  • The formation of that heterochromatin structure is known to be essential for the kinetochore formation on the chromosome centromere. (eurekalert.org)
  • The kinetochore is composed of more than one hundred proteins and serves as the binding site for microtubules that are attached to opposite ends of the cell and will physically pull the two identical chromosomes apart. (scienceblog.com)
  • Without a centromere and a kinetochore, a chromosome would be lost during cell division. (scienceblog.com)
  • We found that although CENP-A is essential for specifying the site of kinetochore formation, CENP-T and CENP-C can act as key components to drive assembly of a functional kinetochore capable of binding microtubules to allow accurate chromosome segregation," concludes first author Dr. Karen Gascoigne. (scienceblog.com)
  • During chromosome segregation, the kinetochore serves as an attachment point for microtubules, which exert strong forces as they winch the chromosomes apart. (eurekalert.org)
  • In human cells, a protein complex termed the Constitutive Centromere-Associated Network (CCAN), is critical for recruiting the kinetochore to a specific point on each chromosome. (eurekalert.org)
  • Without the solid foundation provided by the 16-subunit CCAN, the link between chromosome and kinetochore would fail, as would chromosome segregation and cell division. (eurekalert.org)
  • Learning about its organization can tell us how it targets specifically to the right part of the chromosome - the centromere - and the properties that underlie its role in kinetochore stability. (eurekalert.org)
  • The histone protein CENP-A is the epigenetic mark for centromeres, but CENP-A nucleosomes can be sparsely integrated throughout the chromosome without recruiting a kinetochore. (eurekalert.org)
  • Errors made during chromosome segregation e.g., due to a lack or overexpression of a single kinetochore protein, can lead to daughter cells with an abnormal number of chromosomes (aneuploidy). (ieo.it)
  • Condensed chromosomes attach to this framework via a specialized structure on their surface known as the kinetochore. (rupress.org)
  • Accurate chromosome segregation depends on the kinetochore, the complex of proteins that link microtubules to centromeric DNA1. (harvard.edu)
  • We studied the assembly and function of kinetochore components by fusing individual kinetochore proteins to the lactose repressor (LacI) and testing their ability to improve the segregation of a plasmid carrying tandem repeats of the lactose operator (LacO). (harvard.edu)
  • Targeting Ask1, a member of the Dam1/DASH microtubule-binding complex, creates a synthetic kinetochore that performs many functions of a natural kinetochore: it can replace an endogenous kinetochore on a chromosome, biorient sister kinetochores at metaphase of mitosis, segregate sister chromatids, and repair errors in chromosome attachment. (harvard.edu)
  • We conclude that tethering a single kinetochore protein to DNA triggers the assembly of the complex structure that directs mitotic chromosome segregation. (harvard.edu)
  • We observed that the majority of chromatids derived from micronuclei fail to establish a proper kinetochore in mitosis, which is associated with problems in chromosome alignment, segregation and spindle assembly checkpoint activation. (biologists.org)
  • We conclude that the formation of a separate small nuclear entity represents a mechanism for the cell to delay the stable propagation of excess chromosome(s) and/or damaged DNA, by inducing kinetochore defects. (biologists.org)
  • We exploit Rb fusions to study mechanisms of meiotic chromosome segregation when erroneous kinetochore-MT attachments are recognized and destabilized. (upenn.edu)
  • In this study, we show in symmetrically dividing human cells that kinetochore-microtubules associated to old centrosomes are more stable than those associated to young centrosomes, and that this difference favours the accumulation of premature end-on attachments that delay the alignment of polar chromosomes at old centrosomes. (elifesciences.org)
  • Loss of this force in prometaphase not only delays centrosome separation by 5-6 minutes, it also causes massive chromosome alignment and segregation defects due to the formation of syntelic and merotelic kinetochore-microtubule attachments. (biologists.org)
  • One end of each microtubule is attached to a protein-based structure called a kinetochore, which is assembled onto the centromere of each chromosome. (elifesciences.org)
  • Cancer cell lines with hyperstabilized kinetochore MTs have increased segregation errors and elevated chromosomal instability (CIN), but the genetic defects responsible remain largely unknown. (rupress.org)
  • Here we show that activation of the DNA damage response (DDR) during mitosis selectively stabilizes kinetochore-microtubule (k-MT) attachments to chromosomes through Aurora-A and Plk1 kinases, thereby increasing the frequency of lagging chromosomes during anaphase. (aacrjournals.org)
  • The accurate segregation of chromosomes requires the kinetochore, a complex protein machine that assembles onto centromeric DNA to mediate attachment of replicated sister chromatids to the mitotic spindle apparatus. (asm.org)
  • This study reveals an important role for the yeast RSC ATP-dependent chromatin-remodeling complex at the kinetochore in chromosome transmission. (asm.org)
  • Cellular surveillance pathways such as the spindle checkpoint closely monitor kinetochore-microtubule interactions to ensure that chromosome alignment, orientation, and segregation occur with fidelity ( 1 , 62 ). (asm.org)
  • Several studies in the budding yeast S. cerevisiae suggest that chromatin structure is critical for centromere-kinetochore function and chromosome segregation ( 56 , 68 ). (asm.org)
  • In this work we show that one of the components of the Saccharomyces cerevisiae kinetochore, Nkp2, plays an important role in ensuring accurate segregation of chromosomes. (springer.com)
  • Although this protein is not conserved in higher organisms, we show that it interacts with highly conserved components of the kinetochore genetically and regulates chromosome segregation. (springer.com)
  • Kinetochore clustering, frequently observed in yeasts, plays a key role in genome organization and chromosome segregation. (asm.org)
  • In the absence of the metaphase plate arrangement, kinetochore clustering in yeast species is believed to facilitate timely kinetochore-microtubule interactions to achieve bivalent attachments of chromosomes during metaphase. (asm.org)
  • Kinetochore clustering helps in the organization of yeast chromosomes in the Rabl configuration so that chromosome arms lie freely in the nucleoplasm ( 5 ). (asm.org)
  • A series of observations revealed a diverse group of proteins that contribute to the process of kinetochore clustering to ensure proper chromosome segregation. (asm.org)
  • In contrast, Caenorhabditis elegans female meiotic spindles initially shorten in the pole-to-pole axis such that spindle poles contact the outer kinetochore before the start of anaphase chromosome separation. (escholarship.org)
  • The cells depleted of Spc98 showed an aberrant kinetochore localization pattern and massive chromosome segregation errors. (asm.org)
  • The role of the kinetochore during meiotic chromosome segregation in C. elegans oocytes has been a matter of controversy. (rupress.org)
  • During mitosis, microtubules emanating from centrosomes at opposite poles of the cell bind chromosomes through a multiprotein complex called the kinetochore, allowing chromosomes to be pulled apart ( 1 , 2 ). (rupress.org)
  • showed that the kinetochore is required for chromosome alignment and congression during metaphase ( 7 ). (rupress.org)
  • However, they suggested that chromosome segregation was the result of microtubule polymerization between the segregating chromosomes ( Fig. 1 ), resulting in a pushing force exerted onto chromosomes toward the spindle poles in a largely kinetochore-independent manner ( 7 ). (rupress.org)
  • As separating chromosomes move towards the polar cortex at mid anaphase, kinetochore-localized PP1-Sds22 helps to break cortical symmetry by inducing the dephosphorylation and inactivation of ezrin/radixin/moesin proteins at cell poles. (altmetric.com)
  • In summary, this identifies a conserved kinetochore-based phosphatase signal and substrate, which function together to link anaphase chromosome movements to cortical polarization, thereby coupling chromosome segregation to cell division. (altmetric.com)
  • The kinetochore is essential for chromosome segregation and propagation of our species. (cam.ac.uk)
  • Merotelic kinetochore attachment induced by nocodazole washout leads to elevated aneuploidy of a subset of chromosomes, and high rates of anaphase lagging of chromosomes 1 and 2. (scienceopen.com)
  • Interestingly, noncoding RNA (RNA that does not make proteins) in fission yeast transcribed from the chromosome centromere is necessary for the formation of heterochromatin in the centromere itself. (eurekalert.org)
  • Now, a study published by Cell Press in the April 29th issue of the journal Cell , provides fascinating new insight into the complex of proteins that orchestrates the proper segregation of human chromosomes during cell division. (scienceblog.com)
  • During the process of mitosis, DNA and its associated packing proteins are arranged into structures called chromosomes that are duplicated and then segregated. (scienceblog.com)
  • At mitotic entry, kinetochores assemble on the centromeres (CEN) of the replicated chromosomes (sister chromatids) to bi-orient them on the mitotic spindle, a dynamic array of centrosomes (spindle poles), microtubules and microtubule-associated proteins. (ieo.it)
  • Following satisfaction of the SAC and separation of all bi-oriented sisters (by dissolution of the cohesion linkages), kinetochores, motor proteins and spindle regression move the chromosomes into the daughter cells, generating offspring with a correct number of chromosomes. (ieo.it)
  • Using yeast allows for a quick genetic identification of proteins involved in chromosome segregation and for dissecting functional relationships between the involved proteins. (ieo.it)
  • Besides kinetochores we also study proteins regulating rDNA segregation in Saccharomyces cerevisiae . (ieo.it)
  • To identify new proteins involved in chromosome segregation we perform protein affinity purifications and yeast two-hybrid screens. (ieo.it)
  • To address this question, we discuss how environmental conditions affect chromosome segregation and how segregation proteins influence other cell cycle processes. (frontiersin.org)
  • The role of segregation proteins is to control the positioning of chromosomal (or plasmid) DNA during cell division. (frontiersin.org)
  • During chromosome replication, segregation proteins position newly duplicated chromosomal origin of replication ( oriC ) regions and ensure proper chromosome organization. (frontiersin.org)
  • In animal cells, the DNA is arranged within structures called chromosomes and groups of proteins called centrosomes control the process that separates the chromosome copies as the cell divides. (elifesciences.org)
  • Inhibition of DDR proteins, ATM or Chk2, abolishes the effect of DNA damage on k-MTs and chromosome segregation, whereas activation of the DDR in the absence of DNA damage is sufficient to induce chromosome segregation errors. (aacrjournals.org)
  • MAIN RESULTS AND THE ROLE OF CHANCE Immunofluorescent analysis of the CPC subunit Inner Centromere Protein revealed the pool of stably bound CPC proteins was not strictly confined to the inner centromere of prometaphase chromosomes in human zygotes, as observed in later stages of preimplantation development and somatic cells. (eur.nl)
  • When we reduce the proteins responsible for rejuvenation after meiotic S phase, cohesion is lost and meiotic chromosomes missegregate. (prolekare.cz)
  • Saccharomyces cerevisiae kinesin- and dynein-related proteins required for anaphase chromosome segregation. (rupress.org)
  • In this study, the roles of these motor proteins in anaphase chromosome segregation were examined. (rupress.org)
  • A complex between the anaphase promoting factor/cylosome (APC/C), its accessory protein Cdc20 and proteins of the SAC renders APC/C inactive, usually until all chromosomes are properly assembled at the spindle equator (chromosome congression) and under tension from spindle fibres. (uni-bielefeld.de)
  • The findings reveal the proteins' significance in the correct segregation of X-shaped chromosomes - packages of DNA made up of two strands of identical genetic information. (ed.ac.uk)
  • Further analysis revealed that these three proteins are not only essential but also sufficient to maintain the centromere mark on chromosomes from one cell generation to the next. (ed.ac.uk)
  • In addition to ParABS systems, most bacteria harbor condensin complexes, members of the structural maintenance of chromosomes (SMCs) family of proteins found in all kingdoms of life 23 . (nature.com)
  • Harms, et al , 1 used YFP- and mCherry-labeled proteins that bind to specific regions of the chromosome during replication to visualize where the chromosome localizes at different points in the cell cycle. (hamamatsu.com)
  • This work demonstrates that a subset of the CCAN proteins, which form the CENP-T pathway, dominates to ensure successful cell division by binding to a protein complex called the Ndc80 complex, which allows microtubules to attach to chromosomes. (somefind.com)
  • The process of division in bacterial chromosomes is regulated by the Par (partition) proteins, which bind to DNA. (sheffield.ac.uk)
  • The project combines multidisciplinary approaches including biochemistry, single-molecule fluorescence microscopy and bionanotechnology to visualize the chromosome segregation proteins on synthetic surfaces in a cell-free system. (sheffield.ac.uk)
  • Acetylation of histone proteins in chromosomes tends to activate genes or facilitate transcription of genes into mRNA and translation of mRNA into protein. (wcrf.org)
  • Using chromosomes that exhibit a high frequency of supernumerary crossovers in Caenorhabditis elegans , we find that essential chromosomal structures are mispatterned in the presence of multiple crossovers, subjecting chromosomes to improper spindle forces and leading to defects in metaphase alignment. (prolekare.cz)
  • Unequal inheritance of chromosomes (aneuploidy) is a cause of a number of disorders, particularly in humans, even though eukaryotic cells can arrest or delay the transition from metaphase to anaphase if an event critical to the completion of metaphase is impaired. (springer.com)
  • SUMMARY ANSWER Investigation of the regulatory kinase pathways involved in centromeric CPC targeting revealed normal phosphorylation dynamics of histone H2A at T120 (H2ApT120) by Bub1 kinase and subsequent recruitment of Shugoshin, but phosphorylation of histone H3 at threonine 3 (H3pT3) by Haspin failed to show the expected centromeric enrichment on metaphase chromosomes in the zygote. (eur.nl)
  • However, phosphorylation of histone H3 at threonine 3 (H3pT3) by Haspin kinase failed to show the expected centromeric enrichment on metaphase chromosomes in the zygote, but not at later stages. (eur.nl)
  • WIDER IMPLICATIONS OF THE FINDINGS In the zygote, paternal and maternal chromosomes coming from two separate pronuclei, and with contrasting epigenetic signatures, need to be aligned on a single metaphase plate. (eur.nl)
  • On the other hand, kinetochores do not cluster at any stage of the cell cycle in most metazoans, where the formation of the metaphase plate aligns all chromosomes on a single plane. (asm.org)
  • Both of these stages require chromosomes/chromatids to align during metaphase before separating to opposite poles during anaphase. (rupress.org)
  • Mammalian oocytes arrest constitutively at metaphase II in presence of aligned chromosomes, which is due to the activity of the cytostatic factor (CSF). (uni-bielefeld.de)
  • However, the addition to the map of numerous biochemical loci which did not vary between inbred strains has more recently been provided by analysis of mouse × hamster cell hybrids which preferentially segregate murine chromosomes (Lalley et al. (springer.com)
  • The speed at which chromosomes segregate appears to require an active process, but the machinery remains elusive. (wiley.com)
  • Biologists discover that the environment surrounding a cell plays an integral role in its ability to accurately segregate its chromosomes. (mit.edu)
  • Hepatocytes proliferating in regenerating livers, such as the mitotic cell shown here with a mitotic spindle (green) capturing chromosomes (blue), are able to accurately segregate chromosomes, whereas hepatocytes dividing in culture have high levels of chromosome missegregation. (mit.edu)
  • In a paper published this week, they describe how some types of cells rely on signals from surrounding tissue in order to maintain chromosome stability and segregate accurately. (mit.edu)
  • I think the assumption was … a cell would segregate chromosomes the same way in a dish as it would in a tissue because everything was happening inside the cell. (mit.edu)
  • This book describes current knowledge about the mechanisms by which cells segregate their already duplicated chromosomes in preparation for cell division. (doabooks.org)
  • The spindle is an apparatus that segregate chromosomes into the egg. (riken.jp)
  • CENP-T mutants lacking domains for binding to Ndc80, but not similar to CENP-C mutants, revealed a failure of chromosomes to segregate, prevent cells from dividing and ultimately leading to cell death. (somefind.com)
  • Whether bacteria segregate their chromosomes by passive or active mechanisms has been a long-standing debate. (dkfz.de)
  • Microtubules nucleated from the centrosomes (yellow) oscillate between phases of growth and shrinkage `searching' for chromosomes. (nih.gov)
  • In cell-free Xenopus extracts, microtubules are nucleated in the vicinity of chromatin-coated beads in random orientation and are subsequently sorted into an antiparallel microtubule array that surrounds chromosomes. (nih.gov)
  • A motorless version of MCAK that binds centromeres but not microtubules disrupts chromosome segregation during anaphase. (rupress.org)
  • Filaments called microtubules assemble from the centrosomes and attach to the chromosomes. (elifesciences.org)
  • The microtubules first align all the chromosomes in the middle of the cell before pulling them towards the centrosomes as the cell divides. (elifesciences.org)
  • The experiments show that the microtubules that assemble from the older centrosome bind the chromosome more tightly than those that form from the younger centrosome. (elifesciences.org)
  • At the onset of mitosis, cells need to break down their nuclear envelope, form a bipolar spindle and attach the chromosomes to microtubules via kinetochores. (biologists.org)
  • The dynamic regulation of microtubules (MTs) during mitosis is critical for accurate chromosome segregation and genome stability. (rupress.org)
  • In a recombination-defective mutant ( spo11Δ ), the checkpoint delays the biochemical events of anaphase I, suggesting that chromosomes that are attached to microtubules but are not under tension can activate the spindle checkpoint. (sciencemag.org)
  • It was surprising that actin fibers are also involved in segregating chromosomes in eggs, because chromosome segregation is generally thought to rely solely on another type of protein fiber, called microtubules, which make up the spindle. (mpg.de)
  • Using this information it was possible to investigate the function of the two different pools of BubR1 and show that one pool helps establish the connection between kinetochores and microtubules and the other pool controls when the chromosomes should split into the two new daughter cells. (ku.dk)
  • Co-immunoprecipitation experiments showed that satellite I RNA associates with Aurora B, a component of the chromosome passenger complex (CPC) regulating proper attachment of microtubules to kinetochores, in mitotic HeLa cells. (ovid.com)
  • In cell division, microtubules can physically manipulate the chromosomes, pull half of each chromosome for transposition into a daughter cell and half in the other. (somefind.com)
  • However, in contrast to eukaryotic chromosome segregation, replication and segregation are not temporally separated. (wikipedia.org)
  • Based on this observation, scientists have studied the replication and segregation of chromosomes as a phenomenon exclusively internal to the cell. (mit.edu)
  • Unlike eukaryotic cells, chromosome replication and segregation is closely coordinated with cell division. (hamamatsu.com)
  • When an egg is fertilized by a sperm, maternal and paternal chromosomes unite - a new life begins. (mpg.de)
  • Our results suggest that adaptations in mechanisms regulating CPC targeting exist in the human zygote, to ensure symmetric recruitment despite the epigenetic asymmetry between maternal and paternal chromosomes. (eur.nl)
  • This division segregates maternal and paternal chromosomes for production of eggs and sperms, which are the origin of a new life. (riken.jp)
  • Abnormal chromosomal segregation, on the other hand, can cause cell death (apoptosis) or diseases like Down syndrome and cancer. (eurekalert.org)
  • Here we report the identification of chromosomal segregation defects in normal NPCs of the mouse cerebral cortex. (jneurosci.org)
  • Furthermore, the severity of chromosomal segregation errors ranges from mild, where the chromosome deviates a few micrometers from the others, to severe with micronuclei formation. (nature.com)
  • Using our less-invasive live-cell imaging system optimized for long-term imaging for the analysis of molecular dynamics of mammal pre-implantation embryos 12 , the type/severity of early chromosomal segregation errors in pre-implantation embryos can be assessed. (nature.com)
  • We performed embryo transfer after fluorescence observation of chromosomal segregation using mouse embryos obtained by in vitro fertilization (IVF) (a technique where unfertilized eggs retrieved from females are fertilized in vitro with spermatozoa). (nature.com)
  • Through live-cell imaging, single embryo transfer, and genome sequencing at single-cell resolution, we demonstrated that early chromosomal segregation error resulting in aneuploidy in mouse pre-implantation embryos is a developmental risk to the blastocyst, but some blastocysts retain their developmental potential. (nature.com)
  • Karyotype conversion, from mostly telocentric (centromere terminal) to mostly metacentric (centromere internal), typically reflects fixation of Robertsonian (Rb) fusions, a common chromosomal rearrangement that joins two telocentric chromosomes at their centromeres to create one metacentric. (upenn.edu)
  • Thus, GTSE1 inhibition of MCAK activity regulates the balance of MT stability that determines the fidelity of chromosome alignment, segregation, and chromosomal stability. (rupress.org)
  • Persistent errors in chromosome segregation lead to chromosomal instability (CIN), the increased rate of gain or loss of chromosomes within a cell population. (rupress.org)
  • If in humans, for instance, chromosomes are not reliably segregated during egg maturation, this may lead to spontaneous abortion or chromosomal anomalies such as Down Syndrome. (mpg.de)
  • Partitioning bacterial chromosomal DNA into many small volumes during dPCR enabled AST results after short exposure times by 1) precise quantification and 2) a measurement of how antibiotics affect the states of macromolecular assembly of bacterial chromosomes. (caltech.edu)
  • Repeated binding and unbinding of chromosomal segments to these tethering sites eventually can mediate segregation of sister chromosomes by biasing their random movement toward the poles in a Brownian ratchet-like manner. (dkfz.de)
  • Professor Tokio Tani's research group in Kumamoto University found that a mutation in the protein Prp16, which is involved in the splicing reaction that removes intron sequences, makes it impossible to accurately separate chromosomes during cell division. (eurekalert.org)
  • CAMBRIDGE, Mass. (November 19, 2015) - Whitehead Institute researchers have revealed the architecture of a protein complex that plays a foundational role in the machine that directs chromosome segregation during cell division. (eurekalert.org)
  • In the majority of bacterial species, faithful chromosome segregation is mediated by the tripartite ParABS system, consisting of an ATPase protein ParA, a CTPase and DNA-binding protein ParB, and a centromere-like parS site. (jic.ac.uk)
  • The architectural protein H-NS binds nonspecifically to hundreds of sites throughout the chromosome and can multimerize to stiffen segments of DNA as well as to form DNA-protein-DNA bridges. (asm.org)
  • Scientists at the Max Planck Institute (MPI) for Biophysical Chemistry now show in the mouse model that the structural protein actin protects egg cells from mistakes during chromosome segregation. (mpg.de)
  • Here we report two replication-control mechanisms mediated by a chromosome segregation protein, ParB2, encoded by chromosome II of the model multichromosome bacterium, Vibrio cholerae. (epfl.ch)
  • The 39- mers are the strongest inhibitors of chromosome II replication and they mediate inhibition by binding the replication initiator protein. (epfl.ch)
  • Postdoc Gang Zhang investigated how the BubR1 protein functions in the cell, particularly its role at a structure on chromosomes called kinetochores. (ku.dk)
  • Type 1 protein phosphatase acts in opposition to IpL1 protein kinase in regulating yeast chromosome segregation. (asm.org)
  • Conditional ipl1ts mutants missegregate chromosomes severely at 37 degrees C. Here, we report that IPL1 encodes an essential putative protein kinase whose function is required during the later part of each cell cycle. (asm.org)
  • In an effort to identify additional gene products that participate with the Ipl1 protein kinase in regulating chromosome segregation in yeast, a truncated version of the previously identified DIS2S1/GLC7 gene was isolated as a dosage-dependent suppressor of ipl1ts mutations. (asm.org)
  • These results suggest that type 1 protein phosphatase acts in opposition to the Ipl1 protein kinase in vivo to ensure the high fidelity of chromosome segregation. (asm.org)
  • In the present study, reasons for the high frequency of chromosome nondisjunction were studied among descendants of mutants from 18 lines with a decreased expression of the TRF2 protein. (deepdyve.com)
  • Chromosome dimer resolution requires that dif is positioned correctly in the chromosome, and the activity of FtsK, a septum-located protein that coordinates cell division with chromosome segregation. (gla.ac.uk)
  • This mechanism was also supported by the finding that CLIP-associated protein (CLASP)-dependent microtubule polymerization between the segregating chromosomes is essential for chromosome separation ( 8 ). (rupress.org)
  • Here we show that Rb interacts, through an IxCxE motif and specifically during G 2 /M phase, with hsHec1p, a protein essential for proper chromosome segregation. (elsevier.com)
  • Human-chromatin-related protein interactions identify a demethylase complex required for chromosome segregation. (ac.be)
  • A new study is reported in the newspaper nature Cell Biology has gained insight into this process by revealing the details of how protein complexes coincide at the center of chromosomes in places called centromerrals. (somefind.com)
  • At these sites, the protein complexes function as anchors through which cellular structural organizers can redistribute chromosomes in the cell. (somefind.com)
  • Future studies will be carried out on understanding how similar protein patterns drive chromosome segregation in bacteria. (sheffield.ac.uk)
  • Chromosome segregation and cell division are essential, highly ordered processes that depend on numerous protein complexes. (uni-hd.de)
  • Using gene tagging on bacterial artificial chromosomes, protein localization, and tandem-affinity purification-mass spectrometry, the MitoCheck consortium has analyzed about 100 human protein complexes, many of which had not or had only incompletely been characterized. (uni-hd.de)
  • These data independently confirm the presence of aneuploid NPCs and demonstrate the occurrence of mitotic segregation defects in normal cells that can mechanistically account for aneuploidy in the CNS. (jneurosci.org)
  • Thus, laggards and micronuclei are indicators of chromosome missegregation and aneuploidy. (jneurosci.org)
  • In the pre-implantation embryo, aneuploidy resulting from chromosome segregation error is considered responsible for pregnancy loss. (nature.com)
  • Other errors can result in the chromosomes being unevenly divided between daughter cells, a condition called aneuploidy. (mit.edu)
  • You are cordially invited to the EMBO Workshop on Chromosome Segregation and Aneuploidy, to be held on June 22-26, 2013, on the estate of Nyenrode Castle in Breukelen, The Netherlands. (biotechsciencenews.com)
  • Human chromosomes vary widely in size, gene density and other parameters that might generate bias in mis-segregation rates, however technological limitations have precluded a systematic and high throughput analysis of chromosome-specific aneuploidy. (scienceopen.com)
  • Our findings suggest that inherent properties of specific chromosomes can influence chromosome mis-segregation and aneuploidy, with implications for studies on aneuploidy in human disease. (scienceopen.com)
  • Importantly, it is currently unknown whether the defects in SCC in Tex19.1-/- ES cells are also caused by changes in AcSMC3, and if increased aneuploidy is caused by chromosome mis-segregation. (ed.ac.uk)
  • Despite wide variation between human chromosomes in size, gene density, interphase nuclear territory and non-centromeric heterochromatin it is currently unknown whether these or additional characteristics generate bias in mis-segregation rates, since high-throughput methods to analyse chromosome-specific aneuploidy are lacking. (ncri.org.uk)
  • This implies that recurrent aneuploidy in human pathologies may be attributable in part to chromosome-specific alteration rates. (ncri.org.uk)
  • Our findings suggest that non-random mis-segregation could act in parallel with evolutionary selection to drive recurrent aneuploidy in cancer, particularly if non-random mis-segregation operates throughout tumour development. (ncri.org.uk)
  • Further characterisation of signatures of aneuploidy following different insults to mitotic fidelity may lead to the ability to infer mechanisms underlying cancer CIN by analysing the identity and behaviour of individual chromosomes prone to mis-segregation. (ncri.org.uk)
  • In order for chromosomes to equally divide, it is necessary first to bind the filamentous spindle fiber to a specific region, the centromere, of the chromosome. (eurekalert.org)
  • They examined why splicing mutants show chromosome segregation abnormalities and found that splicing mutant strains do not normally form heterochromatin in the chromosome centromere region. (eurekalert.org)
  • Duplicated chromosomes are attached together at a region called the centromere. (scienceblog.com)
  • Both sth1 and sfh1 mutants exhibit altered centromeric and centromere-proximal chromatin structure and increased missegregation of authentic chromosomes. (asm.org)
  • Centromere function in the budding yeast Saccharomyces cerevisiae is conferred by an unusually compact 125-bp DNA sequence comprised of three conserved elements, CDEI, CDEII, and CDEIII, which are necessary and sufficient to mediate segregation of sister chromatids ( 12 , 29 ). (asm.org)
  • The centromere is found where identical chromosome strands are tethered together and forms a point of attachment for long fibres, called the mitotic spindle, that pull them apart as the cell divides. (ed.ac.uk)
  • Scientists at the University of Edinburgh sought to better understand how the centromere is assembled and targeted to the correct position in specific sections of chromosomes. (ed.ac.uk)
  • Chromosome conformation capture reveals SMC-mediated long-range interactions around ten centromere-like parS sites clustered at the replication origin ( oriC ). (nature.com)
  • This suggests the possibility that such a system could be used to generate human artificial chromosomes. (scienceblog.com)
  • Escherichia coli cells depleted of the conserved GTPase, ObgE, show early chromosome-partitioning defects and accumulate replicated chromosomes in which the terminus regions are colocalized. (wiley.com)
  • top-2 ( it7 ) chromosome-segregation defects observed during anaphase I are not due to residual entanglements incurred during meiotic DNA replication and are not dependent on SPO-11 -induced double-strand DNA breaks. (genetics.org)
  • Cells lacking GTSE1 have defects in chromosome alignment and spindle positioning as a result of MT instability caused by excess MCAK activity. (rupress.org)
  • Reducing GTSE1 levels in CIN cancer cell lines reduces chromosome missegregation defects, whereas artificially inducing GTSE1 levels in chromosomally stable cells elevates chromosome missegregation and CIN. (rupress.org)
  • These defects frequently give rise to eggs with an incorrect number of chromosomes," Schuh comments on her department's latest research findings. (mpg.de)
  • Additionally, the chromosomes with extra interfering crossovers often exhibited segregation defects in anaphase I, with a high incidence of chromatin bridges that sometimes created a tether between the chromosome and the first polar body. (prolekare.cz)
  • Finally, inhibiting the DDR during mitosis in cancer cells with persistent DNA damage suppresses inherent chromosome segregation defects. (aacrjournals.org)
  • Our findings indicate that the bulk of anaphase chromosome segregation in S. cerevisiae is accomplished by the combined actions of these three motors. (rupress.org)
  • What causes this high error rate is unknown, as mechanisms used to ensure proper chromosome segregation in mammalian embryos are poorly described. (eur.nl)
  • In Drosophila oocytes, microtubule asters first assemble at NEBD away from chromosomes in the absence of discrete PCM-containing MTOCs. (nih.gov)
  • Knockdown of Gie in Drosophila cells also blocked normal sister chromosome segregation but did not block the progression of mitosis. (sciencemag.org)
  • Using molecular markers we mapped two regions of the Drosophila genome that appear to exhibit differences between D. simulans and D. sechellia in their regulation of sex chromosome segregation distortion. (genetics.org)
  • Male Drosophila lack synapsis, but nonetheless, their chromosomes closely associate with the nuclear periphery at prophase I. To explore the functional significance of this association, we characterize mutations in nuclear blebber ( nbl ), a gene required for both spermatocyte nuclear shape and meiotic chromosome transmission. (genetics.org)
  • The association of meiotic chromosomes with the nuclear periphery is particularly striking in Drosophila males, in which paired homologs occupy discreet domains closely apposed to the nuclear membrane. (genetics.org)
  • As most solid tumors are aneuploid it has been hypothesized that chromosome missegregation drives or supports the cancer transformation process. (ieo.it)
  • Overexpression of the full-length DIS2S1/GLC7 gene results in chromosome missegregation in wild-type cells and exacerbates the mutant phenotype in ipl1 cells. (asm.org)
  • TYPE II DNA topoisomerases play a critical role in chromosome fidelity by alleviating topological stresses that arise within chromosomes. (genetics.org)
  • Research reveals that the external environment of epithelial cells influences the fidelity of chromosome segregation. (mit.edu)
  • We propose that chromosome position on the spindle provides spatial cues for the fidelity of meiotic cell division. (upenn.edu)
  • The IPL1 gene is required for high-fidelity chromosome segregation in the budding yeast Saccharomyces cerevisiae. (asm.org)
  • This adaptation may come at a price regarding chromosome segregation fidelity. (eur.nl)
  • Sad1 is nonessential for viability in C. neoformans but is required for proper growth and high-fidelity chromosome segregation. (asm.org)
  • The asymmetrically dividing budding yeast, _Saccharomyces cerevisiae_, relies upon alignment of the mitotic spindle along the mother-to-daughter cell polarity axis for the fidelity of chromosome segregation. (bilkent.edu)
  • Rb thus increased the fidelity of chromosome segregation mediated by hsHec1p in a heterologous yeast system. (elsevier.com)
  • These patterns are mainly attributed to selection processes due to an assumption that human chromosomes carry equal chance of being mis-segregated into daughter cells when fidelity of cell division is compromised. (scienceopen.com)
  • Structural Maintenance of Chromosomes (SMC) complexes contribute ubiquitously to chromosome organization-segregation. (researchsquare.com)
  • MCAK MT depolymerase activity must therefore be precisely controlled in time and cellular space to ensure both chromosome alignment and segregation and to avoid CIN. (rupress.org)
  • in this study, ploidy of blastomeres of 2-cell embryos was investigated by single-cell genome sequencing after live-cell imaging of 1st mitosis to link the imaging data of chromosome segregation and ploidy of embryo. (nature.com)
  • Hence, the segregation of the genome is coordinated in time and space. (ieo.it)
  • The segregation of sister chromatids during cell division ensures that each daughter cell receives a complete copy of the genome. (asm.org)
  • During the construction of yeast artificial chromosome (YAC) libraries to facilitate mapping of the human genome, two YACs may be cotransformed into the same yeast cell, making further analysis very difficult. (ox.ac.uk)
  • We show that human chromosome mis-segregation is non-random, with a small subsets of chromosomes contributing to genome change. (ncri.org.uk)
  • The parABS system, which is used for segregation of chromosomes in a large number of bacterial lineages, including Caulobacter crescentus , is far from universal, however ( 6 , 7 ), and is not used by Escherichia coli , for example, where the mukBEF SMC complex operates ( 8 , 9 ). (pnas.org)
  • H-NS has been suggested to contribute to the orderly folding of the Escherichia coli chromosome in the highly compacted nucleoid. (asm.org)
  • The Xer site-specific recombination system functions in Escherichia coli to ensure that circular plasmids and chromosomes are in the monomeric state prior to segregation at cell division. (gla.ac.uk)
  • Much of the previous work on bacterial replication and chromosome segregation has focused on Caulobacter crescentus , Escherichia coli , and Pseudomonas aeruginosa , with the finding that the mechanics of the process differs among different bacterial species. (hamamatsu.com)
  • They find that, in Escherichia coli , the oscillating Min system mediates a novel Brownian ratchet-type mechanism of chromosome segregation, challenging the conventional view that the Min system only functions in mid-cell determination. (dkfz.de)
  • Chromosome segregation by the Escherichia coli Min system. (dkfz.de)
  • However, only a few studies have examined the relationship between chromosome segregation errors during early cleavage and development. (nature.com)
  • An increased number of aneuploid blastomeres in embryos may result from chromosome segregation errors during early division. (nature.com)
  • To test whether our de novo- induced micronucleated cells displayed higher amounts of chromosome segregation errors than cells with a single nucleus, we scored segregation errors by live-cell imaging of the mitosis following micronucleus formation ('2nd division', see Fig. 1 A for experimental setup). (biologists.org)
  • In reality, there are sometimes errors in the process of separating chromosomes into daughter cells, known as chromosome mis-segregation. (mit.edu)
  • Low tension is a widely accepted mechanism for recognizing errors, but whether chromosome position regulates MT attachments is unknown. (upenn.edu)
  • Oocytes with reduced actin tend to have chromosome segregation errors. (mpg.de)
  • In the future, we want to find out whether actin also protects human eggs from chromosome segregation errors," Schuh says. (mpg.de)
  • Actin protects mammalian eggs against chromosome segregation errors. (mpg.de)
  • The cells in the dek15 endosperm and embryo exhibited precocious sister chromatid separation and other chromosome segregation errors, including misaligned chromosomes, lagging chromosomes, and micronuclei, resulting in a high percentage of aneuploid cells. (plantcell.org)
  • In a woman's thirties, errors in meiotic chromosome segregation rise exponentially, significantly increasing the probability that she will conceive a fetus with Down Syndrome (Trisomy 21). (prolekare.cz)
  • The age-related reduction in expression of components of the SAC in mammalian oocytes may act synergistically with spindle and other cell organelles' dysfunction, and a partial loss of cohesion between sister chromatids to predispose oocytes to errors in chromosome segregation. (uni-bielefeld.de)
  • and (10) the consequences of errors in chromosome segregation. (doabooks.org)
  • Expression of Rb reduced chromosome segregation errors fivefold in yeast cells sustained by a temperature-sensitive (ts) hshec1-113 allele and enhanced the ability of wild-type hsHec1p to suppress lethality caused by a ts smc1 mutation. (elsevier.com)
  • The findings are important for the understanding of chromosome errors in human eggs. (riken.jp)
  • For over a century, the abnormal movement or number of centrosomes has been linked with errors of chromosomes distribution in mitosis. (elsevier.com)
  • I compared the incidence of errors commonly associated with chromosome mis-segregation between Tex19.1-/- and control cells, and found an increase in micronuclei in interphase Tex19.1-/- ES cells. (ed.ac.uk)
  • My data supports the model that loss of Tex19.1 in ES cells causes changes in the amount of AcSMC3 associated with chromatin, and errors in chromosome segregation. (ed.ac.uk)
  • In bacteria with circular chromosomes, homologous recombination can generate chromosome dimers that cannot be segregated to daughter cells at cell division. (gla.ac.uk)
  • 8. Martinez-Perez E, Schvarzstein M, Barroso C, Lightfoot J, Dernburg AF, Villeneuve AM. Crossovers trigger a remodeling of meiotic chromosome axis composition that is linked to two-step loss of sister chromatid cohesion. (prolekare.cz)
  • Sister chromatid cohesion is first established during DNA replication or shortly thereafter and is maintained as chromosomes condense and align themselves on the mitotic spindle until the onset of anaphase. (asm.org)
  • Sister chromatid cohesion and segregation is a critical step for guaranteeing the equal distribution of genetic materials between daughter cells. (plantcell.org)
  • In both mitotic and meiotic cells, sister chromatid cohesion is required for accurate chromosome segregation, and the cohesive linkages that hold sister chromatids together depend on the cohesin complex which forms a DNA-entrapping ring [1] , [2] . (prolekare.cz)
  • As combined motor activity was diminished by mutation, both the velocity and extent of chromatin movement were reduced, suggesting a direct role for all three motors in generating a chromosome-separating force. (rupress.org)
  • Cohesins: chromatin architects in chromosome segregation, cont. (mysciencework.com)
  • During anaphase I, dissolution of chromosome arm cohesion leads to reductional segregation of homologs. (nih.gov)
  • Mechanistically, we show that these chromosomes are prone to cohesion fatigue that results in anaphase lagging upon release from nocodazole or Eg5 inhibition. (scienceopen.com)
  • Moreover, we demonstrate that established methods to elevate chromosome mis-segregation due to disruption of bipolar spindle assembly depend in part on a mitotic delay and cohesion fatigue that impacts correction of improper chromosome-spindle attachments, and acutely affects chromosomes 1 and 2. (ncri.org.uk)
  • Expression of a dominant-negative form of Gie1 in a cultured human cell line caused the appearance of micronuclei and abnormal chromosome segregation. (sciencemag.org)
  • These results suggest that early chromosome segregation error causing micronuclei formation affects ploidy and development to blastocyst but does not necessarily cause developmental failure after the blastocyst stage. (nature.com)
  • The presence of micronuclei is a hallmark of chromosome instability. (biologists.org)
  • This study revealed for the first time that intron sequences, originally thought to be useless sequences that were normally removed in the process of gene expression, have an important function of controlling heterochromatin formation in chromosome centromeres. (eurekalert.org)
  • The selective chromatid segregation model has been proposed as a mechanism for the asymmetric cell division that initiates a cascade of gene regulation events in offspring cells to develop brain laterality in embryogenesis. (omicsonline.org)
  • A. The involved gene was on the Y chromosome. (coursehero.com)
  • D. The involved gene was on the X chromosome. (coursehero.com)
  • The disruption in tissue architecture likely causes mechanical changes that disrupt segregation, in a manner that is independent of mutations or gene expression changes. (mit.edu)
  • The discovery of these fundamental processes could aid the development of gene therapies by allowing researchers to make artificial chromosomes capable of self-renewing. (ed.ac.uk)
  • Wood, JS & Hartwell, LH 1982, ' A dependent pathway of gene functions leading to chromosome segregation in saccharomyces cerevisiae ', Journal of Cell Biology , vol. 94, no. 3, pp. 718-726. (elsevier.com)
  • A low concentration of CENP-E inhibitor (CENP-Ei) inhibits chromosome congression, causing misalignment of one or few chromosomes. (biologists.org)
  • They then analyzed the cause of abnormality of centromeric heterochromatin formation in splicing mutant strain, showing that introns in nontranslatable RNA are transcribed from chromosome centromeres, and that artificial removal of introns induced abnormalities in heterochromatin formation. (eurekalert.org)
  • Kinetochores are macromolecular proteinaceous assemblies that are assembled on centromeres and attach chromosomes to the spindle fibres and regulate the accurate transmission of genetic material to daughter cells. (springer.com)
  • Here, using fluorescence In-Situ hybridization (FISH) imaging of specific centromeres coupled with high-throughput single cell analysis, as well as single-cell sequencing we show that human chromosome mis-segregation is non-random. (scienceopen.com)
  • Most bacterial chromosomes and low copy number plasmids encode an active segregation machinery called ParABS to partition replicated DNA prior to cell division. (sheffield.ac.uk)
  • The authors used numerical simulations to demonstrate that entropy alone is not sufficient to complete segregation of bacterial chromosomes. (dkfz.de)
  • During this stage, segregation occurs by a process similar to that during mitosis, except that in this case prophase II is not preceded by a round of DNA replication. (wikipedia.org)
  • Failure of proper segregation during prophase II can also lead to aneuploid gametes. (wikipedia.org)
  • This is because, at the end of meiotic prophase I, CO recombination provides a physical link that holds homologous chromosome pairs together. (wikipedia.org)
  • In many organisms, homolog pairing and synapsis at meiotic prophase depend on interactions between chromosomes and the nuclear membrane. (genetics.org)
  • ASSOCIATIONS between chromosomes and the nuclear envelope during meiotic prophase are a widely conserved phenomenon important for proper chromosome transmission. (genetics.org)
  • Finally, we show that TOP-2 associates with chromosomes in meiotic prophase and that chromosome association is disrupted in the germ lines of top-2 ( it7 ) mutants. (genetics.org)
  • Humans, for example, have 23 pairs of chromosomes, and the chromosomes within each pair are said to be homologous because they are similar to each other in a number of ways, including length and shape. (elifesciences.org)
  • Figure: Localization of BubR1 (red) on chromosomes (blue) during cell division. (ku.dk)
  • In addition, further research is needed to determine to what extent the differences we observed in H3T3 phosphorylation dynamics and CPC localization affect chromosome attachment. (eur.nl)
  • These results suggest that satellite I RNA is involved in chromosome segregation through controlling activity and centromeric localization of Aurora B kinase. (ovid.com)
  • We suggest that dtopors plays a structural role in spermatocyte lamina that is critical for multiple aspects of meiotic chromosome transmission. (genetics.org)
  • These data suggest that the TLSPs contribute to multiple aspects of meiotic chromosome dynamics. (caltech.edu)
  • During mitosis, kinetochores orchestrate chromosome transmission from the mother into the daughter cells. (ieo.it)
  • The attachment of chromosomes to the mitotic spindle is mediated by kinetochores, multiprotein complexes that assemble onto centromeric DNA. (asm.org)
  • It represents a surveillance mechanism that halts cells in M-phase in the presence of unattached chromosomes, associated with accumulation of checkpoint components, in particular, Mad2, at the kinetochores. (uni-bielefeld.de)
  • For eukaryotes, the configuration of the system in the last eukaryotic common ancestor (LECA) is an important facet of reconstructions of eukaryote evolutionary history ( Fig. 1 A ). Most importantly, there is no evidence for common descent between known bacterial chromosome segregation systems and the eukaryotic KT, suggesting an evolutionary discontinuity in the inheritance of a fundamental and universal cellular process. (pnas.org)
  • Regardless, the LECA cell(s) possessed a set of structures that indicate a nucleus with pretty much the same organization as in modern eukaryotes and which needed to faithfully separate chromosomes ( 13 ). (pnas.org)
  • In a wide range of eukaryotes, chromosome segregation occurs through anaphase A, in which chromosomes move toward stationary spindle poles, anaphase B, in which chromosomes move at the same velocity as outwardly moving spindle poles, or both. (escholarship.org)
  • This work has led to the discovery of previously unknown, evolutionarily conserved subunits of the anaphase-promoting complex and the gamma-tubulin ring complex--large complexes that are essential for spindle assembly and chromosome segregation. (uni-hd.de)
  • Furthermore, removal of Nkp2 in these mutants restores normal levels of segregation. (springer.com)
  • These connections establish bridges across the nuclear envelope and allow for interactions between meiotic chromosomes and cytoskeletal actin. (genetics.org)
  • Here, we review the various models for the formation of the ParABS complex and describe its role in segregating the origin-proximal region of the chromosome. (jic.ac.uk)
  • Xer site-specific recombination at dif, a 28-bp site located in the replication terminus region of the chromosome, converts dimers to monomers through the sequential action of the XerC and XerD recombinases. (gla.ac.uk)
  • The tight choreography requires that each region of the chromosome moves to a specific part of the cell at precisely defined times during the cell cycle. (hamamatsu.com)
  • During mitosis chromosome segregation occurs routinely as a step in cell division (see mitosis diagram). (wikipedia.org)
  • Upon proper segregation, a complete set of chromatids ends up in each of two nuclei, and when cell division is completed, each DNA copy previously referred to as a chromatid is now called a chromosome. (wikipedia.org)
  • Proper chromosome segregation during cell division is essential in all domains of life. (jic.ac.uk)
  • Cortical CDC42 depends on polarization directed by chromosomes, which are positioned near the cortex to allow the asymmetric cell division. (ovid.com)
  • When it comes time for one of these cells to duplicate, each chromosome is first replicated to generate a pair of identical chromosomes called sister chromatids, which subsequently separate in a cell division process known as mitosis to produce two identical daughter cells. (elifesciences.org)
  • Cell division requires the precise coordination of chromosome segregation and cytokinesis. (altmetric.com)
  • Dynein is involved in the movement of chromosomes and positioning the mitotic spindles for cell division. (wikipedia.org)
  • How do bacterial cells ensure each daughter cell gets one and only one copy of the chromosome during cell division? (hamamatsu.com)
  • This sets up the ter region of both chromosomes to locate towards the midcell, the site where the new pole will form once cell division is complete. (hamamatsu.com)
  • Our work disappears from a previous consensus by demonstrating that it is CENP-T, not CENP-C, which acts through the Ndc80 complex for successful cell division by ensuring proper and fast chromosome segregation,' says principal author Masatoshi Hara. (somefind.com)
  • These bacterial positioning systems form distinctive patterns within the cells, and are involved in important cellular functions such as DNA segregation, cell division and motility. (sheffield.ac.uk)
  • Therefore, the bacterial Min system coordinates cell division and chromosome segregation. (dkfz.de)
  • The precise regulation of microtubule (MT) dynamics is essential to the accurate execution of mitosis and the faithful segregation of chromosomes. (rupress.org)
  • In mouse oocytes, multiple MTOCs (yellow) assemble microtubule aster-like structures in the vicinity of chromosomes that subsequently are organized into a bipolar spindle. (nih.gov)
  • The precursor cells of eggs, the so-called oocytes, harbor - as all other cells in our body - two copies of each chromosome. (mpg.de)
  • Vogt E, Kirsich-Volders M, Parry J, Eichenlaub-Ritter U. Spindle formation, chromosome segregation and the spindle checkpoint in mammalian oocytes and susceptibility to meiotic error. (uni-bielefeld.de)
  • Spindle formation, chromosome segregation and the spindle checkpoint in mammalian oocytes and susceptibility to meiotic error", MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS , vol. 651, 2008, pp. 14-29. (uni-bielefeld.de)
  • My findings also indicate that ES cells may be a more tractable cellular model than mouse oocytes to analyse the role of TEX19.1 and AcSMC3 on chromosome segregation. (ed.ac.uk)
  • This delays the alignment of the chromosomes that are connected to the old centrosome, as this process requires a flexible attachment. (elifesciences.org)
  • Moreover, in case the two chromosome copies fail to separate properly as cells divide, the older centrosome is more likely to receive both chromosome copies at the expense of the other centrosome. (elifesciences.org)
  • In this review, we examine the role of the ubiquitin system in the events relating to centriole duplication and centrosome separation, and discuss how the disruption of these functions impacts chromosome segregation. (elsevier.com)
  • Microtubule (−)-ends are focused away from chromosomes to form the spindle poles. (nih.gov)
  • In the 'extrusion-capture' model, replication through an anchored replisome provides the force to move daughter chromosomes to the poles ( Lemon and Grossman, 2001 ). (wiley.com)
  • Moreover, in these cells, chromosomes are often retained at the spindle poles and do not correctly move to the center. (mpg.de)
  • The spindle shortens an additional 0.5 μm until the chromosomes are embedded in the spindle poles. (escholarship.org)
  • Chromosomes then separate at the same velocity as the spindle poles in an anaphase B-like movement. (escholarship.org)
  • We conclude that the majority of meiotic chromosome movement is caused by shortening of the spindle to bring poles in contact with the chromosomes, followed by separation of chromosome-bound poles by outward sliding. (escholarship.org)
  • This segregation event takes place in two stages: anaphase A, where chromosomes are pulled toward spindle poles due to microtubule depolymerization, and anaphase B, where spindle poles themselves move farther apart, taking the attached chromosomes with them ( 3 , 4 ). (rupress.org)
  • An alternative model suggested that chromosomes are transported through microtubule-free channels toward the spindle poles by the action of dynein ( 9 ). (rupress.org)
  • Later evidence put in doubt a role for dynein and favored a model in which chromosomes initially separate when the spindle shortens and the poles overlap with chromosomes in an anaphase A-like mechanism. (rupress.org)
  • This is then followed by separation of chromosome-bound poles by outward microtubule sliding in an anaphase B-like fashion ( 10 ). (rupress.org)
  • Here we found that CDC42 signaling from the cell cortex regulated microtubule tyrosination to induce spindle asymmetry and that non-Mendelian segregation depended on this asymmetry. (ovid.com)
  • Finally, RSC is not required for centromeric deposition of the histone H3 variant Cse4p, suggesting that RSC plays a role in reconfiguring centromeric and flanking nucleosomes following Cse4p recruitment for proper chromosome transmission. (asm.org)
  • Proper positioning of dif in the chromosome and of FtsK at the septum is required to sense the multimeric state of newly replicated chromosomes and restrict complete Xer reactions to dimeric chromosomes. (gla.ac.uk)
  • Sad1 is required for proper chromosome segregation. (asm.org)
  • This tension is required for proper bi-orientation of sister chromosomes as well as for satisfaction of the spindle assembly checkpoint and entry into anaphase. (cam.ac.uk)
  • Cells have evolved to develop molecules and control mechanisms that guarantee correct chromosome segregation and ensure the proper distribution of genetic material to daughter cells. (mysciencework.com)
  • This segregation process is also facilitated by cohesin. (wikipedia.org)
  • Overall, my results suggest that TEX19.1 has a role in the maintenance of SCC and cohesive cohesin in the murine mitotic cell model, ensuring appropriate chromosome segregation. (ed.ac.uk)