Chromatids: 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)Sister Chromatid Exchange: 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.Chromosome Segregation: The orderly segregation of CHROMOSOMES during MEIOSIS or MITOSIS.Chromosomal Proteins, Non-Histone: 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.Crossing Over, Genetic: 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.Cell Cycle Proteins: 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.Separase: 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.Anaphase: The phase of cell nucleus division following METAPHASE, in which the CHROMATIDS separate and migrate to opposite poles of the spindle.Centromere: 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.Mitosis: 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.Metaphase: 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.Meiosis: 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.Chromosomes: 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)Securin: 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.Chromosome Aberrations: Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.Kinetochores: Large multiprotein complexes that bind the centromeres of the chromosomes to the microtubules of the mitotic spindle during metaphase in the cell cycle.Chromosomes, Fungal: Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell.Spindle Apparatus: 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.Nuclear Proteins: 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.Saccharomyces cerevisiae Proteins: 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.Chromosome Pairing: The alignment of CHROMOSOMES at homologous sequences.Recombination, Genetic: 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.DNA Repair: The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.Mutagens: Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.Saccharomyces cerevisiae: 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.DNA Damage: Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.DNA Replication: The process by which a DNA molecule is duplicated.Lymphocytes: White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.Chromosomes, Human: 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.Mutagenicity Tests: Tests of chemical substances and physical agents for mutagenic potential. They include microbial, insect, mammalian cell, and whole animal tests.Bloom Syndrome: An autosomal recessive disorder characterized by telangiectatic ERYTHEMA of the face, photosensitivity, DWARFISM and other abnormalities, and a predisposition toward developing cancer. The Bloom syndrome gene (BLM) encodes a RecQ-like DNA helicase.Prophase: 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.Mutation: 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.Fungal Proteins: Proteins found in any species of fungus.DNA Breaks, Double-Stranded: Interruptions in the sugar-phosphate backbone of DNA, across both strands adjacently.Azure Stains: PHENOTHIAZINES with an amino group at the 3-position that are green crystals or powder. They are used as biological stains.Acetyltransferases: Enzymes catalyzing the transfer of an acetyl group, usually from acetyl coenzyme A, to another compound. EC 2.3.1.Cell Cycle: 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.S Phase: Phase of the CELL CYCLE following G1 and preceding G2 when the entire DNA content of the nucleus is replicated. It is achieved by bidirectional replication at multiple sites along each chromosome.Schizosaccharomyces pombe Proteins: 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.Chromosome Breakage: A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.Rad51 Recombinase: A Rec A recombinase found in eukaryotes. Rad51 is involved in DNA REPAIR of double-strand breaks.Aneuploidy: 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).Schizosaccharomyces: A genus of ascomycetous fungi of the family Schizosaccharomycetaceae, order Schizosaccharomycetales.Nondisjunction, Genetic: 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.Ubiquitin-Protein Ligase Complexes: 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).DNA Topoisomerases, Type II: 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.RecQ Helicases: A family of structurally-related DNA helicases that play an essential role in the maintenance of genome integrity. RecQ helicases were originally discovered in E COLI and are highly conserved across both prokaryotic and eukaryotic organisms. Genetic mutations that result in loss of RecQ helicase activity gives rise to disorders that are associated with CANCER predisposition and premature aging.Anaphase-Promoting Complex-Cyclosome: 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.Mitomycin: An antineoplastic antibiotic produced by Streptomyces caespitosus. It is one of the bi- or tri-functional ALKYLATING AGENTS causing cross-linking of DNA and inhibition of DNA synthesis.In Situ Hybridization, Fluorescence: 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.Genomic Instability: An increased tendency of the GENOME to acquire MUTATIONS when various processes involved in maintaining and replicating the genome are dysfunctional.Mad2 Proteins: 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.Bromodeoxyuridine: A nucleoside that substitutes for thymidine in DNA and thus acts as an antimetabolite. It causes breaks in chromosomes and has been proposed as an antiviral and antineoplastic agent. It has been given orphan drug status for use in the treatment of primary brain tumors.DNA, Catenated: 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.Chromosomal Instability: An increased tendency to acquire CHROMOSOME ABERRATIONS when various processes involved in chromosome replication, repair, or segregation are dysfunctional.De Lange Syndrome: A syndrome characterized by growth retardation, severe MENTAL RETARDATION, short stature, a low-pitched growling cry, brachycephaly, low-set ears, webbed neck, carp mouth, depressed nasal bridge, bushy eyebrows meeting at the midline, hirsutism, and malformations of the hands. The condition may occur sporadically or be associated with an autosomal dominant pattern of inheritance or duplication of the long arm of chromosome 3. (Menkes, Textbook of Child Neurology, 5th ed, p231)Interphase: 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).Micronuclei, Chromosome-Defective: Defective nuclei produced during the TELOPHASE of MITOSIS or MEIOSIS by lagging CHROMOSOMES or chromosome fragments derived from spontaneous or experimentally induced chromosomal structural changes.DNA-Binding Proteins: 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.Multiprotein Complexes: Macromolecular complexes formed from the association of defined protein subunits.G2 Phase: The period of the CELL CYCLE following DNA synthesis (S PHASE) and preceding M PHASE (cell division phase). The CHROMOSOMES are tetraploid in this point.Mitomycins: A group of methylazirinopyrroloindolediones obtained from certain Streptomyces strains. They are very toxic antibiotics used as ANTINEOPLASTIC AGENTS in some solid tumors. PORFIROMYCIN and MITOMYCIN are the most useful members of the group.Meiotic Prophase I: 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.Facial DermatosesSynaptonemal Complex: 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.DNA: 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).Chromatin: 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.Demecolcine: An alkaloid isolated from Colchicum autumnale L. and used as an antineoplastic.Gamma Rays: Penetrating, high-energy electromagnetic radiation emitted from atomic nuclei during NUCLEAR DECAY. The range of wavelengths of emitted radiation is between 0.1 - 100 pm which overlaps the shorter, more energetic hard X-RAYS wavelengths. The distinction between gamma rays and X-rays is based on their radiation source.Endopeptidases: A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.Replication Protein C: A DNA-binding protein that consists of 5 polypeptides and plays an essential role in DNA REPLICATION in eukaryotes. It binds DNA PRIMER-template junctions and recruits PROLIFERATING CELL NUCLEAR ANTIGEN and DNA POLYMERASES to the site of DNA synthesis.Gene Conversion: The asymmetrical segregation of genes during replication which leads to the production of non-reciprocal recombinant strands and the apparent conversion of one allele into another. Thus, e.g., the meiotic products of an Aa individual may be AAAa or aaaA instead of AAaa, i.e., the A allele has been converted into the a allele or vice versa.Chondroitin Sulfate Proteoglycans: Proteoglycans consisting of proteins linked to one or more CHONDROITIN SULFATE-containing oligosaccharide chains.Aurora Kinases: 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.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Ectromelia: Gross hypo- or aplasia of one or more long bones of one or more limbs. The concept includes amelia, hemimelia, phocomelia, and sirenomelia.HeLa Cells: 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.Telangiectasis: Permanent dilation of preexisting blood vessels (CAPILLARIES; ARTERIOLES; VENULES) creating small focal red lesions, most commonly in the skin or mucous membranes. It is characterized by the prominence of skin blood vessels, such as vascular spiders.PhosphoproteinsDNA Helicases: 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.Cyclin B: 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.Telomere: 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.Adenosine Triphosphatases: 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.Micronucleus Tests: Induction and quantitative measurement of chromosomal damage leading to the formation of micronuclei (MICRONUCLEI, CHROMOSOME-DEFECTIVE) in cells which have been exposed to genotoxic agents or IONIZING RADIATION.Cricetulus: A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.Saccharomycetales: 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.Chromosome Structures: Structures which are contained in or part of CHROMOSOMES.Protein-Serine-Threonine Kinases: A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.DNA, Fungal: Deoxyribonucleic acid that makes up the genetic material of fungi.Models, Genetic: 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.X-Rays: Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard X-rays are the higher energy, shorter wavelength X-rays. Soft x-rays or Grenz rays are less energetic and longer in wavelength. The short wavelength end of the X-ray spectrum overlaps the GAMMA RAYS wavelength range. The distinction between gamma rays and X-rays is based on their radiation source.Nocodazole: Nocodazole is an antineoplastic agent which exerts its effect by depolymerizing microtubules.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Prometaphase: 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.Rad52 DNA Repair and Recombination Protein: A DNA-binding protein that mediates DNA REPAIR of double strand breaks, and HOMOLOGOUS RECOMBINATION.Aurora Kinase B: 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.Molecular Sequence Data: 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.Genes, cdc: 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).Microtubules: 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.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Spermatocytes: 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.Methyl Methanesulfonate: An alkylating agent in cancer therapy that may also act as a mutagen by interfering with and causing damage to DNA.Cdc20 Proteins: 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.Telophase: The final phase of cell nucleus division following ANAPHASE, in which two daughter nuclei are formed, the CYTOPLASM completes division, and the CHROMOSOMES lose their distinctness and are transformed into CHROMATIN threads.Ethylene Oxide: A colorless and flammable gas at room temperature and pressure. Ethylene oxide is a bactericidal, fungicidal, and sporicidal disinfectant. It is effective against most micro-organisms, including viruses. It is used as a fumigant for foodstuffs and textiles and as an agent for the gaseous sterilization of heat-labile pharmaceutical and surgical materials. (From Reynolds, Martindale The Extra Pharmacopoeia, 30th ed, p794)Ultraviolet Rays: That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.Genes, Fungal: The functional hereditary units of FUNGI.Diploidy: The chromosomal constitution of cells, in which each type of CHROMOSOME is represented twice. Symbol: 2N or 2X.Muntjacs: A genus, Muntiacus, of the deer family (Cervidae) comprising six species living in China, Tibet, Nepal, India, the Malay Peninsula, and neighboring island countries. They are usually found in forests and areas of dense vegetation, usually not far from water. They emit a deep barklike sound which gives them the name "barking deer." If they sense a predator they will "bark" for an hour or more. They are hunted for their meat and skins; they thrive in captivity and are found in many zoos. The Indian muntjac is believed to have the lowest chromosome number in mammals and cell lines derived from them figure widely in chromosome and DNA studies. (From Walker's Mammals of the World, 5th ed., p1366)

The conserved protein kinase Ipl1 regulates microtubule binding to kinetochores in budding yeast. (1/802)

Chromosome segregation depends on kinetochores, the structures that mediate chromosome attachment to the mitotic spindle. We isolated mutants in IPL1, which encodes a protein kinase, in a screen for budding yeast mutants that have defects in sister chromatid separation and segregation. Cytological tests show that ipl1 mutants can separate sister chromatids but are defective in chromosome segregation. Kinetochores assembled in extracts from ipl1 mutants show altered binding to microtubules. Ipl1p phosphorylates the kinetochore component Ndc10p in vitro and we propose that Ipl1p regulates kinetochore function via Ndc10p phosphorylation. Ipl1p localizes to the mitotic spindle and its levels are regulated during the cell cycle. This pattern of localization and regulation is similar to that of Ipl1p homologs in higher eukaryotes, such as the human aurora2 protein. Because aurora2 has been implicated in oncogenesis, defects in kinetochore function may contribute to genetic instability in human tumors.  (+info)

Rec8p, a meiotic recombination and sister chromatid cohesion phosphoprotein of the Rad21p family conserved from fission yeast to humans. (2/802)

Our work and that of others defined mitosis-specific (Rad21 subfamily) and meiosis-specific (Rec8 subfamily) proteins involved in sister chromatid cohesion in several eukaryotes, including humans. Mutation of the fission yeast Schizosaccharomyces pombe rec8 gene was previously shown to confer a number of meiotic phenotypes, including strong reduction of recombination frequencies in the central region of chromosome III, absence of linear element polymerization, reduced pairing of homologous chromosomes, reduced sister chromatid cohesion, aberrant chromosome segregation, defects in spore formation, and reduced spore viability. Here we extend the description of recombination reduction to the central regions of chromosomes I and II. We show at the protein level that expression of rec8 is meiosis specific and that Rec8p localizes to approximately 100 foci per prophase nucleus. Rec8p was present in an unphosphorylated form early in meiotic prophase but was phosphorylated prior to meiosis I, as demonstrated by analysis of the mei4 mutant blocked before meiosis I. Evidence for the persistence of Rec8p beyond meiosis I was obtained by analysis of the mutant mes1 blocked before meiosis II. A human gene, which we designate hrec8, showed significant primary sequence similarity to rec8 and was mapped to chromosome 14. High mRNA expression of mouse and human rec8 genes was found only in germ line cells, specifically in testes and, interestingly, in spermatids. hrec8 was also expressed at a low level in the thymus. Sequence similarity and testis-specific expression indicate evolutionarily conserved functions of Rec8p in meiosis. Possible roles of Rec8p in the integration of different meiotic events are discussed.  (+info)

Sister chromatid-based DNA repair is mediated by RAD54, not by DMC1 or TID1. (3/802)

In the mitotic cell cycle of the yeast Saccharomyces cerevisiae, the sister chromatid is preferred over the homologous chromosome (non-sister chromatid) as a substrate for DNA double-strand break repair. However, no genes have yet been shown to be preferentially involved in sister chromatid-mediated repair. We developed a novel method to identify genes that are required for repair by the sister chromatid, using a haploid strain that can embark on meiosis. We show that the recombinational repair gene RAD54 is required primarily for sister chromatid-based repair, whereas TID1, a yeast RAD54 homologue, and the meiotic gene DMC1, are dispensable for this type of repair. Our observations suggest that the sister chromatid repair pathway, which involves RAD54, and the homologous chromosome repair pathway, which involves DMC1, can substitute for one another under some circumstances. Deletion of RAD54 in S.cerevisiae results in a phenotype similar to that found in mammalian cells, namely impaired DNA repair and reduced recombination during mitotic growth, with no apparent effect on meiosis. The principal role of RAD54 in sister chromatid-based repair may also be shared by mammalian and yeast cells.  (+info)

Characterization of the components of the putative mammalian sister chromatid cohesion complex. (4/802)

Establishing and maintaining proper sister chromatid cohesion throughout the cell cycle are essential for maintaining genome integrity. To understand how sister chromatid cohesion occurs in mammals, we have cloned and characterized mouse orthologs of proteins known to be involved in sister chromatid cohesion in other organisms. The cDNAs for the mouse orthologs of SMC1S.c. and SMC3S.c. , mSMCB and mSMCD respectively, were cloned, and the corresponding transcripts and proteins were characterized. mSMCB and mSMCD are transcribed at similar levels in adult mouse tissues except in testis, which has an excess of mSMCD transcripts. The mSMCB and mSMCD proteins, as well as the PW29 protein, a mouse homolog of Mcd1pS.c./Rad21S.p., form a complex similar to cohesin in X. laevis. mSMCB, mSMCD and PW29 protein levels show no significant cell-cycle dependence. The bulk of the mSMCB, mSMCD and PW29 proteins undergo redistribution from the chromosome vicinity to the cytoplasm during prometaphase and back to the chromatin in telophase. This pattern of intracellular localization suggests a complex role for this group of SMC proteins in chromosome dynamics. The PW29 protein and PCNA, which have both been implicated in sister chromatid cohesion, do not colocalize, indicating that these proteins may not function in the same cohesion pathway. Overexpression of a PW29-GFP fusion protein in mouse fibroblasts leads to inhibition of proliferation, implicating this protein and its complex with SMC proteins in the control of mitotic cycle progression.  (+info)

Chromosomal analysis of peripheral lymphocytes of patients before and after radiation synovectomy with samarium-153 particulate hydroxyapatite. (5/802)

OBJECTIVE: Radiation synovectomy may be indicated for the treatment of chronic synovitis. A number of factors may affect its current use, including availability, limited evidence for its efficacy compared to intra-articular glucocorticoid, and concerns regarding the potential long-term effects of radiation exposure, particularly in younger patients. Specific chromosome-type abnormalities in peripheral lymphocytes can be useful indicators of whole-body radiation exposure. The frequency of these aberrations has been shown to increase in patients who have had radiation synovectomy using yttrium-90 by up to five times compared to baseline levels. Samarium-153 particulate hydroxyapatite (Sm-153 PHYP) is a new radiopharmaceutical currently on trial which appears to have less extra-articular leakage than yttrium-90 compounds. The aim of this study was to identify any increase in specific chromosome-type abnormalities, using published criteria, in patients following Sm-153 PHYP synovectomy of the knee. The 10 patients (five men, five women) in whom the analyses were performed had a mean age of 47 yr (range 28-70 yr). RESULTS: There was no increase in scored chromosome-type abnormalities after Sm-153 PHYP synovectomy. CONCLUSION: This study further supports the relative safety of Sm-153 PHYP compared to other radiopharmaceuticals.  (+info)

Sli15 associates with the ipl1 protein kinase to promote proper chromosome segregation in Saccharomyces cerevisiae. (6/802)

The conserved Ipl1 protein kinase is essential for proper chromosome segregation and thus cell viability in the budding yeast Saccharomyces cerevisiae. Its human homologue has been implicated in the tumorigenesis of diverse forms of cancer. We show here that sister chromatids that have separated from each other are not properly segregated to opposite poles of ipl1-2 cells. Failures in chromosome segregation are often associated with abnormal distribution of the spindle pole-associated Nuf2-GFP protein, thus suggesting a link between potential spindle pole defects and chromosome missegregation in ipl1 mutant cells. A small fraction of ipl1-2 cells also appears to be defective in nuclear migration or bipolar spindle formation. Ipl1 associates, probably directly, with the novel and essential Sli15 protein in vivo, and both proteins are localized to the mitotic spindle. Conditional sli15 mutant cells have cytological phenotypes very similar to those of ipl1 cells, and the ipl1-2 mutation exhibits synthetic lethal genetic interaction with sli15 mutations. sli15 mutant phenotype, like ipl1 mutant phenotype, is partially suppressed by perturbations that reduce protein phosphatase 1 function. These genetic and biochemical studies indicate that Sli15 associates with Ipl1 to promote its function in chromosome segregation.  (+info)

Inherited susceptibility to bleomycin-induced chromatid breaks in cultured peripheral blood lymphocytes. (7/802)

BACKGROUND: Susceptibility to bleomycin-induced chromatid breaks in cultured peripheral blood lymphocytes may reflect the way a person deals with carcinogenic challenges. This susceptibility (also referred to as mutagen sensitivity) has been found to be increased in patients with environmentally related cancers, including cancers of the head and neck, lung, and colon, and, in combination with carcinogenic exposure, this susceptibility can greatly influence cancer risk. The purpose of this study was to assess the heritability of mutagen sensitivity. METHODS: Heritability was determined by use of a maximum likelihood method that employed the FISHER package of pedigree analysis. Bleomycin-induced breaks per cell values for 135 healthy volunteers without cancer were determined. These individuals were from 53 different pedigrees and included 25 monozygotic twin pairs (n = 50), 14 pairs of dizygotes (twin pairs and siblings, n = 28), and 14 families selected on the basis of a first-degree relative who was successfully treated for head and neck cancer and who had no sign of recurrence for at least 1 year. All data were analyzed simultaneously, and different models of familial resemblance were fitted to the data. All P values are two-sided. RESULTS: Our results showed no evidence for the influence of a shared family environment on bleomycin-induced chromatid breaks. Genetic influences, however, were statistically significant (P =. 036) and accounted for 75% of the total variance. CONCLUSIONS: The high heritability estimate of the susceptibility to bleomycin-induced chromatid breaks indicates a clear genetic basis. The findings of this study support the notion that a common genetic susceptibility to DNA damage--and thereby a susceptibility to cancer--may exist in the general population.  (+info)

A functional assay for centromere-associated sister chromatid cohesion. (8/802)

Cohesion of sister chromatids occurs along the entire length of chromosomes, including the centromere where it plays essential roles in chromosome segregation. Here, minichromosomes in the budding yeast Saccharomyces cerevisiae are exploited to generate a functional assay for DNA sequences involved in cohesion. The centromeric DNA element CDEIII was found to be necessary but not sufficient for cohesion. This element was shown previously to be required for assembly of the kinetochore, the centromere-associated protein complex that attaches chromosomes to the spindle. These observations establish a link between centromere-proximal cohesion and kinetochore assembly.  (+info)

*Sister chromatids

A sister chromatid refers to the identical copies (chromatids) formed by the replication of a chromosome, with both copies ... In other words, a sister chromatid may also be said to be 'one-half' of the duplicated chromosome. A pair of sister chromatids ... Biorientation Sister chromatid exchange Kadyk, Lc; Hartwell, Lh (Oct 1992). "Sister chromatids are preferred over homologs as ... There is evidence that, in some species, sister chromatids are the preferred template for DNA repair. Sister chromatid cohesion ...

*Chromatid

Chromatids may be sister or non-sister chromatids. A sister chromatid is either one of the two chromatids of the same ... see articles Sister chromatids and Sister chromatid exchange). Non-sister chromatids, on the other hand, refers to either of ... Sister chromatid exchange (SCE) is the exchange of genetic information between two sister chromatids. SCEs can occur during ... A pair of sister chromatids is called a dyad. Once sister chromatids have separated (during the anaphase of mitosis or the ...

*Sister chromatid exchange

... (SCE) is the exchange of genetic material between two identical sister chromatids. It was first ... Sister chromatid Meiosis Sister chromatid exchange at the US National Library of Medicine Medical Subject Headings (MeSH) " ... the sister chromatid. Evidence indicates that, due to the special nearby relationship they share, sister chromatids are not ... Sister chromatid exchange has also been observed more frequently in B51(+) Behçet's disease. Mitotic recombination in the ...

*Establishment of sister chromatid cohesion

Sister chromatid cohesion refers to the process by which sister chromatids are paired and held together during certain phases ... Wu, F.M., Nguyen, J.V., and Rankin, S. (2010). A conserved motif at the C-terminus of Soroin is required for sister chromatid ... Establishment of sister chromatid cohesion is the process by which chromatin-associated cohesin protein becomes competent to ... Early data suggesting that S phase is crucial to cohesion was based on the fact that after S phase, sister chromatids are ...

*Centromere

... where two identical sister chromatids are most closely in contact. When cells enter mitosis, the sister chromatids (the two ... "Sister chromatid cohesion". Genetics Home Reference. United States National Library of Medicine. May 15, 2011. "p + q = Solved ... The centromere is the part of a chromosome that links a pair of sister chromatids (a dyad). During mitosis, spindle fibers ... Cell biology Chromatid Diploid Genetics Monopolin Pollard, T.D. (2007). Cell Biology. Philadelphia: Saunders. pp. 200-203. ISBN ...

*Single-cell DNA template strand sequencing

Past methods have been used to track the inheritance patterns of chromatids on a per-strand basis and elucidate the process of ... Unfortunately, this method is found to have poor resolution as it can only be observed at the chromatid level. CO-FISH, or ... If the cell was sequenced after more than one generation, a pattern of chromatid assortment can be ascertained for the ... Strand-seq was initially proposed as a tool to identify sister chromatid exchanges. Being a process that is localized to ...

*Interkinesis

Each chromosome still consists of two chromatids. Soni, NK; Soni, Vandana. Fundamentals of Botany. Tata McGraw-Hill Education. ...

*REC8

... is a meiosis-specific component of the cohesin complex that binds sister chromatids in preparation for the two divisions ... However, Rec8 is maintained at centromeres so that sister chromatids are kept joined until anaphase of meiosis II, at which ... Rec8 is sequentially removed from sister chromatids. It is removed from the arms of chromosomes in the first division - ... In the mouse, the homologous protein is a key component of the meiotic cohesion complex, which regulates sister chromatid ...

*Spindle checkpoint

Each chromatid has its own kinetochore, and all of the microtubules that are bound to kinetochores of sister chromatids radiate ... As it happens that sister chromatids are attached together and both kinetochores are located back-to-back on both chromatids, ... At the metaphase to anaphase transition, this cohesion between sister chromatids is dissolved, and the separated chromatids are ... the two chromatids) until anaphase. At this point, the two sister chromatids separate and travel to opposite poles in the ...

*Institute for Genetic Engineering and Biotechnology (INGEB), Sarajevo

Sister-chromatid exchange assay; Allium assay; Alamar blue assay; Trypan blue assay. Primary cell lines establishment. Projects ... cytokinesis-block micronucleus cytome assay and sister chromatids exchange assay. Evaluation of cytotoxic and cytostatic ...

*Proliferating cell nuclear antigen

Human homologs of a Saccharomyces cerevisiae complex involved in sister chromatid cohesion establishment". J. Biol. Chem. 278 ( ... Sister-chromatid cohesion factors • Protein kinases • Cell-cycle regulators • Apoptotic factors for details see PCNA has been ...

*Shugoshin N terminal protein domain

It has a role in attaching to the kinetochores, structures on the chromatids where microtubules attach. Shugoshin has a ... It senses tension between sister chromatids during mitosis, and it degrades when they separate preventing cell cycle arrest and ... It does this by preventing the cohesin complex which regulates chromatid separation from prematurely dissociating. Shugoshin ... This results in the sister chromatids remaining tethered. Shugoshin also acts as a spindle checkpoint component. ...

*DNA replication

Because sister chromatids after DNA replication hold each other by Cohesin rings, there is the only chance for the ... Therefore, the resulting sister chromatids cannot separate from each other and cannot divide into 2 daughter cells. When ... The replication factories perform disentanglement of sister chromatids. The disentanglement is essential for distributing the ... chromatids into daughter cells after DNA replication. ...

*Immature ovum

It has duplicated its DNA, so that each chromosome has two chromatids, i.e. 92 chromatids all in all (4C). When meiosis I is ... As such, there is only one chromatid on each chromosome, making the total quantity of chromatids 46. This is twice the number ... However, each chromosome still has two chromatids, making a total of 46 chromatids (1N but 2C). The secondary oocyte continues ... Each chromosome is split between the two ootids, leaving only one chromatid per chromosome. Thus, there are 23 chromatids in ...

*Spindle apparatus

Sister chromatids are disentangled and resolved from one another. Chromosomes also shorten in length, up to 10,000 fold in ... By the end of DNA replication, sister chromatids are bound together in an amorphous mass of tangled DNA and protein that would ... Aurora B is a member of the chromosomal passenger complex and mediates chromosome-microtubule attachment and sister chromatid ... This gives mitotic chromosomes the classic "X" shape seen in karyotypes, with each condensed sister chromatid linked along ...

*Mitosis

In nondisjunction, sister chromatids fail to separate during anaphase. One daughter cell receives both sister chromatids from ... The microtubules then contract to pull the sister chromatids of each chromosome apart. Sister chromatids at this point are ... Each chromosome has two chromatids. The two chromatids are joined at the centromere. Gene transcription ceases during prophase ... The lagging chromatid is excluded from both nuclei and is lost. Therefore, one of the daughter cells will be monosomic for that ...

*Mitotic recombination

If a crossover event between non-sister chromatids affects that locus, then both homologous chromosomes will have one chromatid ... If the chromatids containing different alleles line up on the same side of the plate, then the resulting daughter cells will ... However, if chromatids containing the same alleles line up on the same side, the daughter cells will be homozygous at that ... These include sister chromatid exchange and mechanisms related to DNA double strand break repair by homologous recombination ...

*Cohesin

... each sister chromatid segregates to opposite poles. Without cohesin, the cell would be unable to control sister chromatid ... Cohesins hold sister chromatids together after DNA replication until anaphase when removal of cohesin leads to separation of ... Dissociation of sister chromatids cohesion defines anaphase onset, which establishes two sets of identical chromosomes at each ... The two rings are connected to each other through formation of a bridge that holds the two sister chromatids together. The ...

*Nuclear organization

Cohesin: The cohesin complex was initially discovered as a key player in mitosis, binding sister chromatids together to ensure ... Mehta, GD; Kumar, R; Srivastava, S; Ghosh, SK (2 August 2013). "Cohesin: functions beyond sister chromatid cohesion". FEBS ...

*Kim Nasmyth

Nasmyth has since shown that cohesin forms a ring, that sister chromatids are held together within this ring and that they are ... Using temperature-sensitive mutants of the APC/C he found several genes which are required for sister chromatid cohesion which ... Irniger, S.; Piatti, S.; Michaelis, C.; Nasmyth, K. (21 April 1995). "Genes involved in sister chromatid separation are needed ... Nasmyth, K; Peters, J. M.; Uhlmann, F (2000). "Splitting the chromosome: Cutting the ties that bind sister chromatids". Science ...

*Frank Uhlmann

Uhlmann, F. (2007). "What is your assay for sister-chromatid cohesion?". The EMBO Journal. 26 (22): 4609-4618. doi:10.1038/sj. ... Nasmyth, K; Peters, J. M.; Uhlmann, F (2000). "Splitting the chromosome: Cutting the ties that bind sister chromatids". Science ... subscription required) Uhlmann, F; Lottspeich, F; Nasmyth, K (1999). "Sister-chromatid separation at anaphase onset is promoted ... to establish cohesion between sister chromatids during DNA replication". Genes & Development. 13 (3): 320-33. doi:10.1101/gad. ...

*SMC protein

Losada A, Hirano M, Hirano T (1998). "Identification of Xenopus SMC protein complexes required for sister chromatid cohesion". ... Guacci V, Koshland D, Strunnikov A (1998). "A direct link between sister chromatid cohesion and chromosome condensation ... A pair of SMC1 and SMC3 constitutes the core subunits of the cohesin complexes involved in sister chromatid cohesion. Likewise ... chromosomal proteins that prevent premature separation of sister chromatids". Cell. 91 (1): 35-45. doi:10.1016/S0092-8674(01) ...

*Anaphase-promoting complex

During metaphase, sister chromatids are linked by intact cohesin complexes. When securin undergoes ubiquitination by the APC/C ... In this manner, cyclin A can be degraded while cyclin B and securin are degraded only once sister chromatids have achieved bi- ... The subunit Apc15 plays an important role in APC/CCdc20 activation following the bi-orientation of sister chromatids across the ... Once degraded, separin is released, cohesin is degraded and sister chromatids are prepared to move to their respective poles ...

*SGOL1

Tang Z, Sun Y, Harley SE, Zou H, Yu H (Dec 2004). "Human Bub1 protects centromeric sister-chromatid cohesion through Shugoshin ... A physical mechanism that guarantees the accurate segregation of sister chromatids during mitosis arises from the ring shaped ... Wang X, Dai W (Oct 2005). "Shugoshin, a guardian for sister chromatid segregation". Experimental Cell Research. 310 (1): 1-9. ... This complex encircles the two sister chromatids and resists the pulling force of microtubules. The characteristic X-shape ...

*Premature chromosome condensation

Condensation during the G2 phase yields long chromosomes with two chromatids. PCC was first reported in 1968, of viral-infected ...
Molecular Biology Sci Aug 4, 00 Pol : A DNA Polymerase Required for Sister Chromatid Cohesion Zhenghe Wang, Irene B. Castaño,* Alejandro De Las Peñas,* Carrie Adams, Michael F. Christman Establishment of cohesion between sister chromatids is coupled to replication fork passage through an unknown mechanism. Here we report that TRF4, an evolutionarily conserved gene necessary for chromosome segregation, encodes a DNA polymerase with -polymerase-like properties. A double mutant in the redundant homologs, TRF4 and TRF5, is unable to complete S phase, whereas a trf4 single mutant completes a presumably defective S phase that results in a failure of cohesion between the replicated sister chromatids. This suggests that TRFs are a key link in the coordination between DNA replication and sister chromatid cohesion. Trf4 and Trf5 represent the fourth class of essential nuclear DNA polymerases (designated DNA polymerase kappa) in Saccharomyces cerevisiae and probably in all eukaryotes. Department of ...
Meiotic chromosome condensation is a unique process, characterized by dramatic changes in chromosome morphology that are required for the correct progression of pairing, synapsis, recombination and segregation of sister chromatids. We used an antibody that recognizes a ser 10 phosphoepitope on histone H3 to monitor H3 phosphorylation during meiosis in maize meiocytes. H3 phosphorylation has been reported to be an excellent marker for chromosome condensation during mitotic prophase in animal cells. In this study, we find that on maize mitotic chromosomes only pericentromeric regions are stained; there is little staining on the arms. During meiosis, chromosome condensation from leptotene through diplotene occurs in the absence of H3 phosphorylation. Instead, the changes in H3 phosphorylation at different stages of meiosis correlate with the differences in requirements for sister chromatid cohesion at different stages. Just before nuclear envelope breakdown, histone H3 phosphorylation is seen first ...
Regulator of sister chromatid cohesion in mitosis which may stabilize cohesin complex association with chromatin. May couple sister chromatid cohesion during mitosis to DNA replication. Cohesion ensures that chromosome partitioning is accurate in both meiotic and mitotic cells and plays an important role in DNA repair. Plays a role in androgen-induced proliferative arrest in prostate cells.
Chromosome segregation, transcriptional regulation, and repair of DNA double-strand breaks require the cohesin protein complex. Cohesin holds the replicated chromosomes (sister chromatids) together to mediate sister chromatid cohesion. The mechanism of how cohesion is established is unknown. We found that in budding yeast, the head domain of the Smc3p subunit of cohesin is acetylated by the Eco1p acetyltransferase at two evolutionarily conserved residues, promoting the chromatin-bound cohesin to tether sister chromatids. Smc3p acetylation is induced in S phase after the chromatin loading of cohesin and is suppressed in G1 and G2/M. Smc3 head acetylation and its cell cycle regulation provide important insights into the biology and mechanism of cohesion establishment. ...
Segregation of homologous maternal and paternal centromeres to opposite poles during meiosis I depends on post-replicative crossing over between homologous non-sister chromatids, which creates chiasmata and therefore bivalent chromosomes. Destruction of sister chromatid cohesion along chromosome arms due to proteolytic cleavage of cohesins Rec8 subunit by separase resolves chiasmata and thereby triggers the first meiotic division. This produces univalent chromosomes, the chromatids of which are held together by centromeric cohesin that has been protected from separase by shugoshin (Sgo1/MEI-S332) proteins. Here we show in both fission and budding yeast that Sgo1 recruits to centromeres a specific form of protein phosphatase 2A (PP2A). Its inactivation causes loss of centromeric cohesin at anaphase I and random segregation of sister centromeres at the second meiotic division. Artificial recruitment of PP2A to chromosome arms prevents Rec8 phosphorylation and hinders resolution of chiasmata. Our data are
Shop Sister chromatid cohesion 1 protein ELISA Kit, Recombinant Protein and Sister chromatid cohesion 1 protein Antibody at MyBioSource. Custom ELISA Kit, Recombinant Protein and Antibody are available.
A multisubunit complex, called cohesin, containing Smc1p, Smc3p, Scc1p, and Scc3p, is required for sister chromatid cohesion in mitotic cells. We show here that Smc3p and a meiotic version of Scc1p called Rec8p are required for cohesion between sister chromatids, for formation of axial elements, for reciprocal recombination, and for preventing hyperresection of double-strand breaks during meiosis. Both Rec8p and Smc3p colocalize with chromosome cores independently of synapsis during prophase I and largely disappear from chromosome arms after pachytene but persist in the neighborhood of centromeres until the onset of anaphase II. The eukaryotic cells cohesion apparatus is required both for the repair of recombinogenic lesions and for chromosome segregation and therefore appears to lie at the heart of the meiotic process.
Two sister chromatids must be held together by a cohesion process from their synthesis during S phase to segregation in anaphase. Despite its pivotal role in accurate chromosome segregation, how cohesion is established remains elusive. Here, we demonstrate that yeast Rtt101‐Mms1, Cul4 family E3 ubiquitin ligases are stronger dosage suppressors of loss‐of‐function eco1 mutants than PCNA. The essential cohesion reaction, Eco1‐catalyzed Smc3 acetylation is reduced in the absence of Rtt101‐Mms1. One of the adaptor subunits, Mms22, associates directly with Eco1. Point mutations (L61D/G63D) in Eco1 that abolish the interaction with Mms22 impair Smc3 acetylation. Importantly, an eco1LGpol30A251V double mutant displays additive Smc3ac reduction. Moreover, Smc3 acetylation and cohesion defects also occur in the mutants of other replication‐coupled nucleosome assembly (RCNA) factors upstream or downstream of Rtt101‐Mms1, indicating unanticipated cross talk between histone modifications and ...
The Elg1 Clamp Loader Plays a Role in Sister Chromatid Cohesion. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
Sister chromatid cohesion and homologue pairing at prometaphase I in solo; +, +; snm, and solo; snm mutants. X and Y chromosomes were recognized by probes again
View Notes - Homework _16 with answers from BIO Bio 5A at UC Riverside. Homework#16,02/20/09(Dr.MMG) 1. A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two
HDAC inhibitors are a promising class of anticancer agents (Bolden et al., 2006; Johnstone and Licht, 2003; Yoshida et al., 2003). However, our understanding of how HDAC inhibitors act within cells and why different cell types respond in different ways is limited. We employed the fission yeast S. pombe as a model, because this organism is sensitive to HDAC inhibitors and contains a set of HDAC genes similar to those of mammalian organisms. In the present study, we focused on the mitotic functions of three TSA-sensitive HDACs in fission yeast. Our results suggest that Clr6 negatively regulates APC/C independently of the PKA pathway and Mad2. By contrast, Mis4, the cohesin loader, is positively controlled by HDACs. HDAC inhibitors thus reduce the level of Mis4 and facilitate the exit from mitosis via the assembly of APC/C complex, leading to the direction of sister chromatid separation in dividing cells (Fig. 7D).. Given the known anti-proliferation effects of HDAC inhibitors on tumour cells, our ...
Losada, A., Hirano, M., Hirano, T. (December 2002) Cohesin release is required for sister chromatid resolution, but not for condensin-mediated compaction, at the onset of mitosis. Genes & Development, 16 (23). pp. 3004-3016. ISSN 0890-9369 Losada, A., Hirano, M., Hirano, T. (July 1998) Identification of Xenopus SMC protein complexes required for sister chromatid cohesion. Genes and Development , 12 (13). pp. 1986-97. ISSN 0890-9369 (Print) Losada, A., Hirano, T. (February 2001) Intermolecular DNA interactions stimulated by the cohesin complex in vitro: Implications for sister chromatid cohesion. Current Biology, 11 (4). pp. 268-272. ISSN 0960-9822 Losada, A., Yokochi, T., Hirano, T. (May 2005) Functional contribution of Pds5 to cohesin-mediated cohesion in human cells and Xenopus egg extracts. J Cell Sci, 118 (Pt 10). pp. 2133-41. ISSN 0021-9533 (Print) ...
Chromatin, Chromatid, Chromsome Terminology - posted in General Biology Discussion: Some Questions to which I have found different/conflicting answers depending on what I have read or who I have talked to. Thanks in Advance. 1-Chromatin, chromosomes, and chromatid all consist of DNA AND some sort of proteins? 2-Is the following statement accurate: ALL types/forms of chromatin material and chromatids consist of chromosomes BUT not all types of chromosomes are chromatin or chromatids? 3-An...
MAHSKTRTNDGKITYPPGVKEISDKISKEEMVRRLKMVVKTFMDMDQDSEEEKELYLNLALHLASDFFLK 1 - 70 HPDKDVRLLVACCLADIFRIYAPEAPYTSPDKLKDIFMFITRQLKGLEDTKSPQFNRYFYLLENIAWVKS 71 - 140 YNICFELEDSNEIFTQLYRTLFSVINNGHNQKVHMHMVDLMSSIICEGDTVSQELLDTVLVNLVPAHKNL 141 - 210 NKQAYDLAKALLKRTAQAIEPYITNFFNQVLMLGKTSISDLSEHVFDLILELYNIDSHLLLSVLPQLEFK 211 - 280 LKSNDNEERLQVVKLLAKMFGAKDSELASQNKPLWQCYLGRFNDIHVPIRLECVKFASHCLMNHPDLAKD 281 - 350 LTEYLKVRSHDPEEAIRHDVIVSIVTAAKKDILLVNDHLLNFVRERTLDKRWRVRKEAMMGLAQIYKKYA 351 - 420 LQSAAGKDAAKQIAWIKDKLLHIYYQNSIDDRLLVERIFAQYMVPHNLETTERMKCLYYLYATLDLNAVK 421 - 490 ALNEMWKCQNLLRHQVKDLLDLIKQPKTDASVKAIFSKVMVITRNLPDPGKAQDFMKKFTQVLEDDEKIR 491 - 560 KQLEVLVSPTCSCKQAEGCVREITKKLGNPKQPTNPFLEMIKFLLERIAPVHIDTESISALIKQVNKSID 561 - 630 GTADDEDEGVPTDQAIRAGLELLKVLSFTHPISFHSAETFESLLACLKMDDEKVAEAALQIFKNTGSKIE 631 - 700 EDFPHIRSALLPVLHHKSKKGPPRQAKYAIHCIHAIFSSKETQFAQIFEPLHKSLDPSNLEHLITPLVTI 701 - 770 GHIALLAPDQFAAPLKSLVATFIVKDLLMNDRLPGKKTTKLWVPDEEVSPETMVKIQAIKMMVRWLLGMK 771 - 840 ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
Involved in chromosome cohesion during cell cycle and in DNA repair. Central component of cohesin complex. The cohesin complex is required for the cohesion of sister chromatids after DNA replication. The cohesin complex apparently forms a large proteinaceous ring within which sister chromatids can be trapped. At anaphase, the complex is cleaved and dissociates from chromatin, allowing sister chromatids to segregate.
The present study evaluated the dynamics and regulatory mechanisms of single cohesin molecules. We found that Scc2‐Scc4‐dependent topological loading and cohesin ATPase activity (disengagement of the head domain) are crucial for cohesin translocation along DNA. Consistent with this finding, the ATPase‐dependent translocation of cohesin in budding yeast was described in a previous study (Hu et al, 2011). Although Wapl‐Pds5 promotes the dissociation of cohesin from DNA as previously described (Gandhi et al, 2006; Kueng et al, 2006) (Appendix Fig S2C), we showed that Wapl‐Pds5 renders DNA‐associated cohesin immobile (Fig 2A and B). Considering that the engagement of Smc head domains restrains cohesin movement (Fig 1F), Wapl‐Pds5 may contribute to the tightening of the cohesin ring by associating with SA1, Scc1, and/or Smc3 (Shintomi & Hirano, 2009; Hara et al, 2014; Murayama & Uhlmann, 2015; Ouyang et al, 2016). Therefore, Wapl‐Pds5 may have dual activities: "anti‐establishment ...
Following replication of parental DNA template strands, sister chromatids are expected to have exactly the same DNA sequence except for mutations resulting from...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
Protein modification by ubiquitin and ubiquitin‐like modifiers (UBLs) plays key regulatory roles in numerous aspects of cell biology [1], [2]. Eukaryotic cells express more than a dozen UBLs, which share similar three‐dimensional structures with ubiquitin [1]. While the functions of several UBLs are well understood, others remain poorly characterized. Among these are UBL5 (known as Hub1 in yeast), which is unique among UBLs in that it lacks the C‐terminal glycine used for covalent conjugation to target proteins [3], [4]. However, UBL5 displays strong sequence conservation across eukaryotes, suggesting that it has a fundamentally important cellular function. Studies of Hub1 in the yeasts revealed that it is required for pre‐mRNA splicing. S. pombe Hub1 is an essential gene, and loss of Hub1 protein results in pre‐mRNA splicing defects, likely reflecting its interaction with the spliceosomal protein Snu66 (known as SART1 in mammalian cells) and perhaps other splicing factors [5], [6]. In ...
The Shugoshin/Aurora circuitry that controls the timely release of cohesins from sister chromatids in meiosis and mitosis is widely conserved among eukaryotes, although little is known about its function in organisms whose chromosomes lack a localized centromere. Here we show that Caenorhabditis elegans chromosomes rely on an alternative mechanism to protect meiotic cohesin that is shugoshin-independent and instead involves the activity of a new chromosome-associated protein named LAB-1 (Long Arm of the Bivalent). LAB-1 preserves meiotic sister chromatid cohesion by restricting the localization of the C. elegans Aurora B kinase, AIR-2, to the interface between homologs via the activity of the PP1/Glc7 phosphatase GSP-2. The localization of LAB-1 to chromosomes of dividing embryos and the suppression of mitotic-specific defects in air-2 mutant embryos with reduced LAB-1 activity support a global role of LAB-1 in antagonizing AIR-2 in both meiosis and mitosis. Although the localization of a GFP ...
If you have a question about this talk, please contact Duncan Simpson.. Cohesins mediate sister chromatid cohesion, which is essential for chromosome segregation and postreplicative DNA repair. In addition, cohesins appear to regulate gene expression and enhancer-promoter interactions. These noncanonical functions remained unexplained because knowledge of cohesin-binding sites and functional interactors in metazoans was lacking. We show that the distribution of cohesins on mammalian chromosome arms is not driven by transcriptional activity. Instead, mammalian cohesins occupy a subset of DNase I hypersensitive sites, many of which contain sequence motifs resembling the consensus for CTCF , a DNA -binding protein with enhancer blocking function and boundary element activity. We find cohesins at most CTCF sites and show that CTCF is required for cohesin localization to these sites. Recruitment by CTCF suggests a rationale for noncanonical cohesin functions and, because CTCF binding is sensitive to ...
The sister chromatids of each chromosome split apart, and the spindle fibers pull each sister chromatid (now a separate chromosome) from each pair toward opposite poles, much as a rope-tow pulls a skier up a mountain. Telophase begins as sister chromatids reach opposite poles. Once the chromatids have reached opposite poles, the spindle apparatus falls apart, and the nuclear membrane re-forms. Mitosis is complete ...
Class cohesion is considered as one of the most important object-oriented software attributes. High cohesion is, in fact, a desirable property of software. Many different metrics have been suggested in the last several years to measure the cohesion of classes in object-oriented systems. The class of structural object-oriented cohesion metrics is the most in-vestigated category of cohesion metrics. These metrics measure cohesion on structural information extracted from the source code. Empirical studies noted that these metrics fail in many situations to properly reflect cohesion of classes. This paper aims at exploring the use of hierarchical clustering techniques to improve the measurement of cohesion of classes in object-oriented systems. The proposed approach has been evaluated using three particular case studies. We also used in our study three well-known structural cohesion metrics. The achieved results show that the new approach appears to better reflect the cohesion (and structure) of classes
The number of chromatids present during the prophase state of mitosis is double the number of chromosomes. The specific number depends on the number of chromosomes in the cell. Human beings, for...
1056 Hypersensitivity to radiation exposure has been suggested to be a risk factor for the development of breast cancer. In this case-control study of 323 young women (≤55 years) with newly diagnosed sporadic breast cancer and 326 cancer-free controls frequency-matched with patients on age, sex, and ethnicity, we examined the radiosensitivity as measured by the frequency of chromatid breaks induced by gamma-radiation exposure in the G2 phase of phytohemagglutinin-stimulated lymphocytes from short-term cultures of fresh blood samples. We found that the averaged chromatid breaks per cell from 50 well-spread metaphases were statistically significantly higher in breast cancer patients (mean = 0.51 breaks/cell, standard deviation = 0.22) than that in the controls (0.44 ± 0.16) (P value ,0.001). The frequency of chromatid breaks per cell above the median of control subjects was associated with twofold increased risk for breast cancer (OR = 2.02, 95% CI = 1.46 to 2.80). A dose-response relationship ...
i.sister chromatids split apart 2.Spindle draws them to opposite poles 3. Anaphase begins with the release of linker of sister chromatids iv. chromatids are pulled to the spindle pole v.sets of chromosomes to opposite ends of the ...
Overview of DNA transcription, translation, and replication during mitosis and meiosis. Learn about chromosomes, chromatids, and chromatin.
Putative GTPase With A Role In Biogenesis Of RNA Pol II And PolIII; May Be Involved In Assembly Of RNA Polymerases II And III And In Their Transport Into The Nucleus; May Have A Role In Sister Chromatid Cohesion; Contains A Gly-Pro-Asn Motif In The G Domain; Similar To Npa3p And Gpn2p
then the second metaphase. this time the chromosomes instead of the bivalents line up on the equator of the spindle. second anaphase: The 2 chromatids (a chromosome is made of 2 chromatids) divide. they move away from each other. now last but not least the second telophase where again cytoplasm divides and 4 cells are formed. each with half the chromosomes needed: 23!! (in a human ...
In preparation for cell division (either meiosis or mitosis), the chromosomes replicate, forming an identical strand. These two strands remain side-by-s...
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 ...
Summary The ring-shaped cohesin complex brings together distant DNA domains to maintain, express, and segregate the genome. Establishing specific chromosomal linkages depends on cohesin recruitment to defined loci. One such locus is the budding yeast centromere, which is a paradigm for targeted cohesin loading. The kinetochore, a multiprotein complex that connects centromeres to microtubules, drives the recruitment of high levels of cohesin to link sister chromatids together. We have exploited this system to determine the mechanism of specific cohesin recruitment. We show that phosphorylation of the Ctf19 kinetochore protein by a conserved kinase, DDK, provides a binding site for the Scc2/4 cohesin loading complex, thereby directing cohesin loading to centromeres. A similar mechanism targets cohesin to chromosomes in vertebrates. These findings represent a complete molecular description of targeted cohesin loading, a phenomenon with wide-ranging importance in chromosome segregation and, in ...
The cohesin complex ensures accurate sister chromatid segregation during cell division but it also seems to play an important role in development. For example, mutations in several cohesin components are associated with the human developmental disorder Cornelia de Lange syndrome (CdLS). Until now, there has been no animal model for this syndrome but, on p. 3191, Zhang and co-workers report that mice lacking the cohesin regulatory protein PDS5B are born with developmental abnormalities reminiscent of CdLS. Pds5B-deficient mice, like people with CdLS, exhibit abnormal skeletal patterning, heart defects and cleft palates, they report. Unexpectedly, however, the researchers did not find any chromosome cohesion defects in Pds5B-/- cells. Furthermore, they detected high PDS5B expression in post-mitotic neurons of wild-type mice, identified a DNA-binding domain in mouse PDS5B and showed that the protein localizes to the nucleolus. Overall, these results suggest that PDS5B and the cohesin complex might ...
Rationale: A cell has DNA strands of different replication ages because DNA replication is semi-conservative. Double-stranded DNA molecules possess one DNA strand that is one generation older than the other. Non-sister chromatids containing newly synthesized DNA and old DNA strands are non-randomly partitioned between mother and daughter cells. Stem cells are presumed to non-randomly segregate chromatids to determine cell fate of daughter cells, although experimental evidence is lacking. Resident cardiac progenitor cells (CPC) present in the adult heart have been used for cell-based treatment of myocardial damage but the factors determining the stemness and lineage commitment of these cells are poorly understood. Cardio protective kinase Pim-1 increases asymmetric cell division in vivo, proliferation and commitment of CPCs after adaptive transfer in pathological injury model but its role in non-random segregation is unknown.. Objective: Establish role of Pim-1 on non-random chromatid ...
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 ...
Separase Separase is a protein that is a cornerstone of cell division. Serperase is also known as Separin or Esp1. It allows for replicated chromosomes to be separated from their sister chromatids and pulled to opposite poles of the cell by the mitotic spindle, allowing for microfilaments to dissect the cell in half causing two genetically identical daughter cells from the single mother cell in mitosis or some haploid cells in Meiosis. The sister chromatids are held together by a protein called Cohesin, Separase catalyses and breaksdown cohesin allowing the sister chromatids to break apart, which in turn allows the mitotic spindle to draw the chromatids to either sides of the cell. Separase is crucial to the cell division process, not only does it physically separate the sister chromatids, it triggers the start of the anaphase period of cell division. Separase causes the cell to replicate accurately and on some occasions cause some problems if the protein is present or absent in excess ...
Free, official coding info for 2018 ICD-10-CM O45.023 - includes detailed rules, notes, synonyms, ICD-9-CM conversion, index and annotation crosswalks, DRG grouping and more.
Free, official coding info for 2018 ICD-10-CM O45.021 - includes detailed rules, notes, synonyms, ICD-9-CM conversion, index and annotation crosswalks, DRG grouping and more.
This gene encodes the homolog of the Drosophila melanogaster Nipped-B gene product and fungal Scc2-type sister chromatid cohesion proteins. The Drosophila protein facilitates enhancer-promoter communication of remote enhancers and plays a role in developmental regulation. It is also homologous to a family of chromosomal adherins with broad roles in sister chromatid cohesion, chromosome condensation, and DNA repair. The human protein has a bipartite nuclear targeting sequence and a putative HEAT repeat. Condensins, cohesins and other complexes with chromosome-related functions also contain HEAT repeats. Mutations in this gene result in Cornelia de Lange syndrome, a disorder characterized by dysmorphic facial features, growth delay, limb reduction defects, and mental retardation. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008 ...
Baxter J, Aragón L, 2010, Physical linkages between sister chromatids and their removal during yeast chromosome segregation., Cold Spring Harb Symp Quant Biol, Vol: 75, Pages: 389-394 The fidelity of chromosome inheritance is of paramount importance to all living organisms. In eukaryotic cells, the strategy to ensure physical segregation of chromosomes to daughter cells relies on two basic steps ordered in time: an initial linkage, or cohesion, of sister chromatids and its timely and complete dissolution during anaphase. The current view is that these two basic steps are accomplished around the regulation of a protein complex called cohesin that serves as clamp brackets distributed at intervals throughout the genome. However, many of the DNA metabolic activities during interphase also produce physical linking of chromatids. For example, during replication, intertwines between sister chromatids are formed. Here, we review our understanding of the processes that generate physical linkages ...
The Frequency and Clinical Significance of Sister Chromatid Exchange in the Lymphocyte of Gastric Cancer Patient Exposed to Hypoxia
(KudoZ) English to German translation of sister chromatid exchange: Schwesterchromatid-Austausch [alprostadil product characteristics - Medical: Pharmaceuticals (Medical)].
Knockdown of several components of the spliceosome results in premature loss of SCC, thus preventing the stable attachment of microtubules and the bi‐orientation of chromatids (van der Lelij et al, 2014; Sundaramoorthy et al, 2014; Watrin et al, 2014). Some of these factors, such as SNW1 (a component of a NTC‐related subcomplex), PRPF8 (a key coordinator of splicing catalysis associated with U5 snRNP) or MAFP1 (which associates transiently in the context of spliceosomal rearrangements previous to catalysis), are believed to have core functions in the splicing process. Their impact on cell division, however, raised the possibility that they display specific functions in mitotic progression different from splicing (Hofmann et al, 2010). To address this issue, Petronczki and colleagues analyzed in detail a set of 33 spliceosome components previously reported to alter mitosis when downregulated (Neumann et al, 2010). In this new study, knockdown of 26 out of these 33 splicing factors tested ...
Homologous chromosomes do not pair during mitosis, so there is no opportunity for crossing over to occur. Crossing over between non-sister chromatids of homologous chromosomes occurs in meiosis...
The exchange of genetic material means that new combinations of genes are created on two of the four chromatids: Stretches of DNA with maternal gene copies are mixed with stretches of DNA with paternal copies. This creation of new gene combinations is called "recombination" and is very important for evolution, since it increases the amount of genetic material that evolution can act upon. A statistical technique known as linkage analysis uses the frequency of recombination to infer the location of genes, such as those that increase a persons risk for certain diseases.. At the beginning of metaphase I, the nuclear envelope has dissolved, and specialized protein fibers called microtubules have formed a spindle apparatus, as also occurs in the metaphase of mitosis. These microtubules then attach to the kinetochore protein disks on the two centromeres of the homologous pair of chromosomes. However, there is an important difference between mitosis and meiosis in the way this attachment occurs. In ...
View Notes - Handout 7 (for students) from BICD BICD100 at UCSD. Duyen-Anh Pham BICD 100 [email protected] Key Terms : • Chromosome vs. Chromatid vs. chromatin • Centromere and Kinetochore •
Rec8 is a prominent component of the meiotic prophase chromosome axis that mediates sister chromatid cohesion, homologous recombination and chromosome synapsis. Here, we explore the prophase roles of Rec8. (i) During the ...
Separase, A Caspase-like Cysteine Protease; Promotes Sister Chromatid Separation By Mediating Dissociation Of The Cohesin Scc1p From Chromatin; Inhibits Protein Phosphatase 2A-Cdc55p To Promote Mitotic Exit; Inhibited By Pds1p; Relative Distribution To The Nucleus Increases Upon DNA Replication Stress
When you make the baby, call your teacher over and explain how you did it. Again, the student will run the meiosis animation, looking at the cell in the big meiosis window with "Crossover Controlled" option on. When the animation stops in the middle of the process, the student will be told to click on a chromatid. This time, s/he should search for the chromatid that has the M allele. By clicking on one chromatid with an M and on one with an m, the student will see the exchange take place that results in a gamete containing a chromosome with a B+ and an M allele. S/he should then follow the same process for the cell from the other parent. After s/he chooses and fertilizes the proper gametes, the resulting baby should be normal for both sickle cell and methemoglobin. There are a couple of places where problems could arise in this exercise. If the student clicks on the allele itself, nothing will happen and you will hear cries of anguish. Similarly, if s/he clicks too close to the centromere ...
Reactome is pathway database which provides intuitive bioinformatics tools for the visualisation, interpretation and analysis of pathway knowledge.
An illustration of chromosome, with its parts. (1) Chromatid. One of the two identical parts of the chromosome after S phase. (2) Centromere. The point where the two chromatids touch, and where the microtubules attach. (3) Short arm (4) Long arm ...
Function: Corrects defective DNA strand-break repair and sister chromatid exchange following treatment with ionizing radiation and alkylating agents ...
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The special process of cell division by which part exchange takes place between the non-sister chromatids of homologous chromosomes is known as crossing ov
Oh ... I see now ... when the chromosomes replicate they become chromatids. Then they are the same and that makes them sisters. That makes alot of sense. And it means I shouldnt doubt myself lol. GAH it makes too much sense now that I look back at it. Thank you soooo very much for the help ...
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Imagine over your head a sprinkling of light, like stars...the Big Dipper and zoom in on the North Star. ( Can happen that you feel that the star becomes immensely large like a blanket spread over the horizon, shiny silvery white, which makes sense as it lies aligned with the earths axis in the middle of the corona. ) ...
Now several years later we moved on and we found out that securin bound to this protein which we now called Separase and we didnt know…and Separase was required for the onset of anaphase. You could not separate sister chromatids without Separase. So we had this model that Separase bound securin. Like in that form it was inactive and the whole purpose of the anaphase promoting complex was to destroy the securin, liberate the Separase and then the Separase went off and did something magical to the chromosomes and maybe the spindle apparatus that would cause the sister chromatids to be pulled to opposite poles. And one of the big questions was what did Separase do, and it was really work that was done by a postdoc in my lab at the time a guy called Frank Uhlmann, who really cracked this problem. We had meanwhile identified many of the proteins that were directly involved in holding sister chromatids together. And again it was the discovery of the anaphase promoting complex and therefore the ...
Fusion of critically short or damaged telomeres is associated with the genomic rearrangements that support malignant transformation. We have demonstrated the fundamental contribution of DNA ligase 4-dependent classical non-homologous end-joining to long-range inter-chromosomal telomere fusions. In contrast, localized genomic recombinations initiated by sister chromatid fusion are predominantly mediated by alternative non-homologous end-joining activity that may employ either DNA ligase 3 or DNA ligase 1. In this study, we sought to discriminate the relative involvement of these ligases in sister chromatid telomere fusion through a precise genetic dissociation of functional activity. We have resolved an essential and non-redundant role for DNA ligase 1 in the fusion of sister chromatids bearing targeted double strand DNA breaks that is entirely uncoupled from its requisite engagement in DNA replication. Importantly, this fusogenic repair occurs in cells fully proficient for non-homologous ...
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 ...
This paper presents the results of testing gossypol acetate for the possible induction of sister chromatid exchanges (SCEs) in mouse spermatogonial cells in vivofollowing a single intraperitoneal...
Single-cell DNA template strand sequencing, or strand-seq, is a technique for the selective sequencing of a daughter cells parental template strands. This technique has many applications, including the identification of sister chromatid exchanges in the parental cell prior to segregation, the identification of misoriented contigs during alignment of reads to the reference genome, and the assessment of non-random segregation of sister chromatids. Strand-seq (single strand sequencing) was first described in 2012 as a technique to isolate sequenced reads from parental template strands in single-cell DNA libraries. As a proof of concept study, the authors demonstrated the ability to acquire sequence information from the Watson and/or Crick chromosomal strands in an individual DNA library, depending on the mode of chromatid segregation; a typical DNA library will always contain DNA from both strands. The authors were specifically interested in showing the utility of strand-seq in detecting sister ...
Structural maintenance of chromosomes protein 3 (SMC-3) is a nuclear protein that in humans is encoded by the SMC3 gene. A post-translated modified form that is excreted is known as basement membrane-associated chondroitin proteoglycan (bamacan). This gene belongs to the SMC3 subfamily of SMC proteins. The encoded protein occurs in certain cell types as either an intracellular, nuclear protein or a secreted protein. The nuclear form, known as structural maintenance of chromosomes 3, is a component of the multimeric cohesin complex that holds together sister chromatids during mitosis, enabling proper chromosome segregation. Post-translational modification of the encoded protein by the addition of chondroitin sulfate chains gives rise to the secreted proteoglycan bamacan, an abundant basement membrane protein. SMC3 protein appears to participate with other cohesins REC8, STAG3 and SMC1ß in sister-chromatid cohesion throughout the whole meiotic process in human oocytes. Model organisms have been ...
Diastasis recti is a condition where the two right and left sides of the rectus abdominis (your "six-pack" muscle) spreads apart at the bodys mid-line (the linea alba). Separation occurs in response to your uterus pushing against the abdominal wall and pregnancy hormones which soften connective tissue. Separation can occur at any time in the last half of pregnancy but is most problematic after pregnancy when the abdominal wall is weak, when there is no longer a baby inside to aid support. Premature separation can also be seen as early as 20 weeks. ...
We start the exercise at the G1 phase of the cell cycle, where each of four chromosomes is represented by a single noodle held by one person. We describe the maternal and paternal contributions to the diploid cell by reminding the students of the origin of a diploid cell and the process of syngamy that follows fertilization. To further reinforce the concept of homologs, maternal chromosomes are held by female students, paternal chromosomes by male students. The diploid G1 cell then goes through S phase and each chromosome is replicated by adding four additional students; now each chromosome has two sister chromatids and is represented by two identically colored noodles held together at the centromere by a pair of students. Thus, it takes a group of four students (two male, two female) to act as a pair of homologous chromosomes during M&M, one student for each of the four chromatids. This reinforces the origin, structure, and function of sister chromatids.. For mitosis, the students will have to ...
Meiosis. Early prophase 1: The chromatin begins to condense following interphase.. Mid-prophase 1: Synapsis aligns homologs, and chromosomes condense further.. Late prophase 1 - prometaphase: The chromosomes continue to coil and shorten. Crossing over results in an exchange of genetic material. In prometaphase the nuclear envelope breaks down.. Metaphase 1: The homologous pairs line up on the equatorial (metaphase) plate.. Anaphase 1: The homologous chromosomes (each with two chromatids) move to opposite poles of the cell.. Telophase 1 : The chromosomes gather into nuclei, and the original cell divides.. Prophase 2: The chromosomes condense again, following a brief interphase (interkinesis)in which DNA does not replicate.. Metaphase 2: The centrosomes of the paired chromatids line up at the equatorial plates of each cell.. Anaphase 2: The chromatids finally separate, becoming chromosomes in their own right, and are pulled to opposite poles. Because of crossing over in prophase 1, each new cell ...
It can happen that a piece of one chromosome may break loose and join on to another. Such translocations have been observed in persons suffering from a specific kind of leukemia.. At the end of prophase I, homologous, non-sister chromatids are held together at chiasmata; sister chromatids, at centromeres.. During prometaphase I and metaphase I, microtubules of the spindle from the centrosomes, which are now on opposite side of the cell, attach via kinetochores to the centromeres of the chromosomes, i.e., to sister pairs. These connections are also random. Any two of the 23 chromosomes may be pulled to one side and the other two to the other side. This introduces a second source of randomness in the final product. In the case of human beings with 23 chromosomes, there are 223 - over eight million - possibilities.. Next, during anaphase I, the spindle fibers pull the chromosomes to either side, with sisters breaking apart at the chiasmata, but remaining together, since the kinetochores are ...
One of the first ATP-dependent chromatin remodeling complexes was first identified and characterized more than a decade ago. Since then, the number of distinct ATP-dependent chromatin remodeling complexes and the variety of roles they play in nuclear processes have become dizzying. Some of the processes include transcription, replication, repair, recombination, and sister chromatid cohesion. The SWI/SNF-related ATP-dependent remodelers are divided into a number of subfamilies, all related by the SWI2/SNF2 ATPase at their catalytic core. In nearly every species where researchers have looked for them, one or more members of each subfamily have been identified. Here I have investigated the ATP-dependent chromatin remodeler ISWI. I have shown that Xenopus ISWI has a critical function in developing neural tissue. Whole mount in situ hybridization shows ISWI localized in neural tissue including the eye and developing neural tube. Injection of antisense ISWI RNA, morpholino oligonucleotides or ...
Looking for online definition of Adhesion and cohesion in the Medical Dictionary? Adhesion and cohesion explanation free. What is Adhesion and cohesion? Meaning of Adhesion and cohesion medical term. What does Adhesion and cohesion mean?
6. at which phase of meiosis the two cells each with separate sister chromatids move towards opposite polesat which phase of meiosis the two cells each with separate sister chromatids move towards opposite ...
ii) A trait is represented by only one Mendelian factor inside a gamete. A gamete similarly contains a single chromosome out of a pair of homologous chromosomes due to meiosis that occurs before the formation of gametes.. (iii) An organism has a specific number of chromosomes. The somatic cells are generally diploid having chromosomes in pairs called homologous pairs. The two chromosomes of each homologous pair resemble each other in their morphology and genetic content. They are derived from the two parents through their gametes. It also contains two Mendelian factors for each character. The factors come from different parents through their gametes.. (iv) Each chromosome replicates during S-phase. It comes to have two sister chromatids. The two chromatids separate and pass into two daughter nuclei and cells during mitosis. Similarly, each allelic pair replicates, with one pair passing into each daughter cell during mitosis. This maintains the similar genetic composition of all the cells of a ...
The fate of cyclophosphamide (50180) (CP) induced lesions causing sister chromatid exchanges (SCEs) in mouse bone marrow and spleen lymphocytes under in-vivo and in-vivo/in-vitro conditions were compared. Measurements of SCEs were taken from 6 to 48 hours following treatment of male CD1-mice with CP injected intraperitoneally at 40mg/kg body weight. For in-vivo assay, mice were treated with 5-brom
What are Non-Disjunction Disorders?! Non-disjunction is a failure of chromosomes to separate properly (i.e there is an imbalance of genetic information) Occurs when: Homologous chromosomes fail to separate properly in Anaphase I Sister chromatids fail to separate properly during Anaphase II Having abnormal amounts of karyotypes will overload the cells, which may result in: The death of the zygote A person with a non-disjunction disorder being born
11. Does the case present special anesthesia challenges?Yes. In general, pediatric cardiac anesthesia demands a thorough understanding of how individual structural abnormalities may affect the delivery and the metabolism of surgical anesthetics. This concern is compounded in the case of conjoined twins, who share a blood supply. A team of five anesthesiologists will monitor the twins-two per girl plus one additional team member-during the separation process. Although anesthesia administered to one of the girls affects both, each child will be individually anesthetized from the beginning of the surgery to prepare for the separation and to enable the anesthesiologists to quickly and accurately meet the needs of each child as their connection is gradually separated ...
The ages at onset of 245 female and 211 male psoriasis (Ps) patients were recorded. The distribution of age of onset in both sexes is bimodal, with separation at the age of 40 years into an early-onset group and a late-onset group. These distributions were normal (Gaussian) with equal variances. These data are compatible with the hypothesis that there are two genotypes for Ps. Further evidence for this hypothesis is provided by the relationship between age of onset and number of affected relatives. The latter, corrected for age at time of study, demonstrates a mixture of two negative binomial distributions. also with likely separation at the age of 40 years. The age distribution of Ps patients reflects the bimodality of age of onset, but with larger means and variances.. ...
Mitosis Vocabulary. Mitosis -the process of cell division including division of the nucleus.. Cancer -disorder caused when cells lose the ability to control growth and continue to divide.. Interphase -part of the cell cycle when the cell is not dividing. G1 -phase of the cell cycle after cell division, growth and day to day life of a cell.. S Phase -Replication or synthesis of DNA and associated proteins that happens before cells divide.. G2 -Phase of the cell cycle when cells prepare for cell division by making more organelles and cytoplasm.. Diffusion - How most water soluble materials get into a cell. process by which molecules tend to move from an area of higher concentration to an area of lower concentration.. Chromosome -Thread like structure with in the nucleus containing genetic information. Made of DNA coiled around proteins.. Chromatid -half of a duplicated chromosome. One of two "sister" parts, makes half of the "X"(middle is Centromere). Centromere -area where sister chromatids of a ...
Folding of mammalian genomes into spatial domains is critical for gene regulation. CTCF and cohesin control domain location by folding domains into loop structures, which are thought to be highly stable. Combining genomic, biochemical and single-molecule imaging approaches, we show that although CTCF and cohesin can physically interact, CTCF binds chromatin much more dynamically than cohesin (~1 min vs. ~22 min residence time). Moreover, after unbinding, CTCF quickly rebinds another cognate site unlike cohesin (~1 min vs. ~33 min). Thus, CTCF and cohesin form a rapidly exchanging dynamic complex rather than a typical stable complex. Since CTCF and cohesin are required for loop domain formation, our results suggest that chromatin loops constantly break and reform throughout the cell cycle ...
Meiosis 1: Homologous chromosomes pair up and their chromatids wrap around each other. Equivalent portions of the chromatids can be exchanged in crossing over. By the end the homologous pairs have separated with one chromosome from each pair going into one of two daughter ...
No component of this product present at levels greater than or equal to 0.1% is identified as probable, possible or confirmed human carcinogen by IARC. No component of this product present at levels greater than or equal to 0.1% is identified as a carcinogen or potential carcinogen by ACGIH. No component of this product present at levels greater than or equal to 0.1% is identified as a known or anticipated carcinogen by NTP. No component of this product present at levels greater than or equal to 0.1% is identified as a carcinogen or potential carcinogen by OSHA. Genotoxicity in vitro - rat - Liver Sister chromatid exchange Signs and Symptoms of Exposure ...
Duplicating chromosomes once each cell cycle produces sister chromatid pairs which separate accurately at anaphase. polytene chromosomes can also separate prior to metaphase through a spindle-independent mechanism termed Separation-Into-Recent-Sisters (SIRS). Both reduplication responses require the spindle assembly checkpoint protein Mad2. While Mad2 delays anaphase separation of metaphase polytene chromosomes Mad2s control of overall mitotic timing ensures efficient SIRS. Our results pinpoint mechanisms enabling continued proliferation after genome reduplication a finding with implications for cancer progression and prevention. DOI: http://dx.doi.org/10.7554/eLife.15204.001 species of fruit fly Stormo and Fox discovered two distinct ways in AR-231453 which cells respond to extra chromosome duplications. One response occurs in cells that were experimentally engineered to undergo an extra chromosome duplication. These cells delay division so that the chromosome separation machinery can somehow ...
Sister chromatid exchange (SCE) analysis is the most sensitive method for assessing chromosome damage induced by chemical mutagens. We report the SCE of peripheral blood lymphocytes in children with primary nephrotic syndrome (NS) treated with chlorambucil. Group I consisted of 20 normal children, group 2 of 14 children with primary NS who had never received a cytotoxic drug and group III of 7 children with primary NS who had received chlorambucil, which was discontinued 6-36 months prior to the study. Group IV consisted of 4 nephrotic children who were receiving chlorambucil therapy during the study. There was no significant increase in SCE in group III compared with group I or group II (P≫0.05). A significant rise in SCE (P|0.05) was seen in all patients in group IV.
La Plata, Argentina. ABSTRACT The effect of co-culturing varying concentrations of pig and human red blood cells (RBCs) on the baseline frequency of sister chromatid exchanges (SCEs) and cell-cycle progression in pig plasma (PLCs) and whole blood leukocyte cultures (WBCs) was studied. No variation in SCE frequency was observed between pig control WBC and PLC. Addition of pig and human RBCs to pig PLCs did not modify the baseline frequency of SCEs. On the other hand, cell proliferation was slower in PLCs than in WBCs. The addition of pig or human RBCs to PLCs accelerated the cell-cycle progression of pig lymphocytes. When RBCs were added to PLCs the concentration and time sequence of RBC incorporation affected the cell-cycle progression of swine lymphocytes. When doses of pig or human RBCs equivalent to those present in WBCs were added immediately after PLC stimulation, the cell-cycle kinetics were similar to those of WBCs. Shorter co-incubation periods or a reduction in the dose of RBCs made ...
To investigate the usefulness of sister chromatid exchange (SCE) analysis in lymphocytes as an indicator for mutagenic effects after in vivo exposure to hexavalent chromium (Cr), SCE frequency was analysed in lymphocytes of 44 Cr platers occupationally exposed to hexavalent Cr and 47 controls. Although urinary Cr analysis confirmed that the Cr platers were exposed to Cr, no effects of the exposure on SCE frequency were found. Smokers, both Cr platers and controls, had a significantly higher SCE frequency than non-smokers. These results suggest that SCE analysis in human lymphocytes is not a good indicator of possible mutagenic effects of exposure to hexavalent Cr.. ...
A method for simultaneously affecting sister chromatid exchange (SCE) in murine alveolar macrophages, regenerating liver and bone marrow cells of hepatectomized mice and in alveolar macrophages and bone marrow cells of nonhepatectomized mice was developed. Both nonhepatectomized and hepatectomized BDF1-mice were given 9 hourly, 2 milliliter injection of bromodeoxyuridine (59143) (BrdU). The follow
More than 5000 passengers of Tokyo subway trains were injured with toxic chemicals including the nerve gas sarin. Most of the victims examined had marked miosis and decreased serum cholinesterase activity. To monitor the genetic aftereffects of sarin exposure, we measured sister chromatid exchanges SCEs of the victims using peripheral blood...
Although the two-step removal systems in mitosis and meiosis are distinct, a common protein complex is implicated in protecting centromeric cohesion during the first step in both cases. Shugoshin/MEI-S332 family proteins collaborate with the phosphatase PP2A to prevent cohesin removal at centromeres [2], [4]. In mitosis, shugoshin-PP2A complexes antagonize SA phosphorylation by mitotic kinases, preventing removal by the prophase pathway (Figure 1A). In meiosis, shugoshin-PP2A antagonizes phosphorylation of Rec8, preventing cleavage by separase (Figure 1B) [2], [4]. A key question has been: What subsequently allows centromeric cohesion to be cleaved by separase in the second step? One proposed model is that, in response to tension across bi-oriented sister kinetochores, shugoshin-PP2A complexes move away from cohesin complexes at inner centromeres, making cohesin susceptible to removal by separase [5], [6]. Newly published studies, described below, propose two additional (related) mechanisms that ...
Anaphase II: We abbreviate diploid as 2n. During metaphase II, sister chromatids are condensed and aligned at the equator of the cell. Adult flamingos lay eggs that hatch into flamingo chicks c. Crossing-over between homologous chromosomes produces chromosomes with new associations of genes and alleles. The possible number of alignments, therefore, equals 2n, where n is the number of chromosomes per set. The arrangement of the paired chromosomes with respect to the poles of the spindle apparatus is random along the metaphase plate. During meiosis II, the sister chromatids within the two daughter cells separate, forming four new haploid gametes. Individual spindle fibres bind to a kinetochore structure on each side of the centromere. Meiosis II: This doubles the variability of gamete genotypes. Gregor Mendel determined his peas had two sets of alleles, one from each parent. The mechanics of meiosis II is similar to mitosis, except that each dividing cell has only one set of homologous ...
Objective: To identify candidate biomarkers correlated with clinical prognosis of patients with bladder cancer (BC). Methods: Weighted gene co-expression network analysis was applied to build a co-expression network to identify hub genes correlated with tumor node metastasis (TNM) staging of BC patients. Functional enrichment analysis was conducted to functionally annotate the hub genes. Protein-protein interaction network analysis of hub genes was performed to identify the interactions among the hub genes. Survival analyses were conducted to characterize the role of hub genes on the survival of BC patients. Gene set enrichment analyses were conducted to find the potential mechanisms involved in the tumor proliferation promoted by hub genes. Results: Based on the results of topological overlap measure based clustering and the inclusion criteria, top 50 hub genes were identified. Hub genes were enriched in cell proliferation associated gene ontology terms (mitotic sister chromatid segregation, mitotic
Temporal control of DNA replication has been implicated in epigenetic regulation of gene expression on the basis of observations that certain tissue-specific genes replicate earlier in expressing than non-expressing cells. Here, we show evidence that several leukocyte-specific genes replicate early in lymphocytes regardless of their transcription and also in fibroblasts, where these genes are never normally expressed. Instead, the heritable silencing of some genes (Rag-1, TdT, CD8alpha and lambda5) and their spatial recruitment to heterochromatin domains within the nucleus of lymphocytes resulted in a markedly delayed resolution of sister chromatids into doublet signals discernable by 3D fluorescence in situ hybridization (FISH). Integration of transgenes within heterochromatin (in cis) did, however, confer late replication and this was reversed after variegated transgene expression. These findings emphasise that chromosomal location is important for defining the replication timing of genes and show
Explain to the hospital diagnosed with orthopedic conditions will have a high femoral bifurcation, small caliber needle. Major bleeding vessels will require sacrifice of the gallbladder to aid in anatomic reduction is required. Upon closure of interstices, and donor cells in the range of 18% [2, 5]. Syngeneic bone marrow aspiration with or without radiation to the remaining wall of a premature separation of an emergency, use a hair stylist or barber who specializes in caring for a diagnosis of dvt, especially in patients with neural inju- ries other: Many trauma surgeons may choose to perform the heim- lich maneuver, how to maintain safety measures. 5. Vomitingmay indicate pyloric obstruction or cardiacorifice obstruction. Nursing interventions 1. Record intake and output every hour if low-risk pregnancy or rupture of a visual eld testing, perimetry, fundus photography, ultrasound biomicroscopy, and retinal nerve ber im- aging. Airway managementmechanical ventilation, vigorous suctioning, oxygen ...
Bharat, Rajdhani, Rajya, Bihar, Maharashtra, Delhi, Uttar Pradesh, Madhya Pradesh, Full Forms, General Knowledge, Current Gk find all your answers on sawalzawab in hindi, the Indias first question answer site in hindi. SawalZawab.com पर अपने सभी उत्तरों को हिंदी में ढूंढें, भारत की पहली Q&A हिंदी में साइट MakeInIndia के तहत सभी हिंदीभाषी नागरिक, लेखक, शिक्षक, विद्यार्थी यहाँ पर हिंदी में कोई भी सवाल पूछ सकते है या फिर अन्य लोगों द्वारा पूछे गए सवाल के उत्तर देकर दे सकते हैं
Rhoades initially proposed that neocentromere activity is the key to the observed preferential transmission of Ab10 (Rhoades 1952). Further genetic analyses demonstrated that neocentromere activity is required but not sufficient for meiotic drive (Dawe and Cande 1996; Hiatt and Dawe 2003a). According to Rhoades model for meiotic drive (Figure 1B), a crossover event must first occur in the region between the centromere and knob of a heterozygous Ab10/N10 pair. This creates a heteromorphic dyad where each homologous chromosome contains one knobbed and one nonknobbed sister chromatid. As anaphase begins, the knobs on all chromosomes are activated as neocentromeres and begin their dramatic poleward movement. The speed and efficiency of neocentromere activity enable knobs to reach the spindle poles ahead of the centromeres (Yu et al. 1997), creating an outward orientation that ultimately delivers knobbed chromatids to the upper and lower cells of the linear tetrad. Since only the bottom cell develops ...
Subject: Lambda Lunch update To: [email protected] Lambda lunch update, 5/26/09: 5/28/09*: Amar Klar "Asymmetric cell division through selective chromatid segregation" 6/4/08*: Dolph Hatfield: "A single codon decodes specifically two amino acids at internal positions of protein: A new wrinkle in the genetic code" 6/11/08*: Masha Kireeva: "Mechanism of sequence-specific pausing of bacterial RNA polymerase" 6/18/09*: ASM and Berlin RNA meeting Review 6/25/09: No Lambda Lunch -- FASEB procaryotic transcription meeting 7/2/09*: Tony Furano 7/16/09*: Michael Laub (MIT) (Bob Weisberg) *Regular lambda lunch at 11:00 AM in Bldg 37, Rm 6107/6041. To schedule seminars, contact Susan Gottesman ...
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 ...
The male and female pronuclei dont fuse, although their genetic material do so. Instead, their membranes dissolve, leaving no barriers between the male and female chromosomes. During this dissolution, a mitotic spindle forms around them to catch the chromosomes before they get lost in the egg cytoplasm. By subsequently performing a mitosis (which includes pulling of chromatids towards centrosomes in anaphase) the cell gathers genetic material from the male and female together. Thus, the first mitosis of the union of sperm and oocyte is the actual fusion of their chromosomes. Each of the two daughter cells resulting from that mitosis have one replica of each chromatid that was replicated in the previous stage. Thus, they are genetically identical. In other words, the sperm and oocyte dont fuse into one cell, but into two identical cells. ...
 Chromatids - the name for each copy of the doubled chromosome.  Centromere - holds the chromatids together until they separate when the cell divides.  See figure 8-2 on page 146.  Each species has its own characteristic number of chromosomes. See table 8-1 on pg  Sex Chromosomes - (X and Y in humans) - determine the sex of an organism. - Females = XX Males = XY
Citation: Anderson, B.E., Zeiger, E., Shelby, M.D., Resnick, M.A., Gulati, D.K., Ivett, J.L., and Loveday, K.S. Chromosome aberration and sister chromatid exchange test results with 42 chemicals. Environ. Molec. Mutagen. Vol. 16 (Suppl 18) (1990) 55- ...
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 ...
SUMMARY: Inhabitants of the Hohhot Region in Inner Mongolia who drink high-fluoride (4-15 mg/L) water were compared for their micronucleus (MN) rate and sister chromatid exchange (SCE) frequency in their peripheral blood lymphocytes. In persons with fluorosis as well as those considered "healthy", the MN rafe and SCE frequency were significantly higher (t test) than in a neighbouring control group drinking low-fluorlde water.. Key words: Endemic fluorosis; Inner Mongolia, Hohhot region; Micronucleus (MN) rate; Sister chromatid exchange (SCE) frequency.. Introduction Although widespread in occurrence, fluorine (as fluoride ion, F-) does not have any known physiological requirement. It is generally accepted, however, that long term over-intake of fluoride may cause skeletal as well as dental fluorosis. Many studies on other toxic effects of fluoride have been made, including whether it alters human genetic material and ultimately leads to more serious harm. (1) At present, various test systems and ...
To investigate the specificity of biological monitoring variables (excretion of phenanthrene and pyrene metabolites in urine) and the usefulness of some biomarkers of effect (alkaline filter elution, {sup}32{end}P postlabeling assay, measurement of sister chromatid exchange)in workers exposed to polycyclic aromatic hydrocarbons (PAHs). 29 coke oven workers and a standardised control group were investigated for frequencies of DNA single strand breakage, DNA protein cross links (alkaline filter elution assay), sister chromatid exchange, and DNA adducts ({sup}32{end}P postlabeling assay) in lymphocytes. Phenanthrene and pyrene metabolites were measured in 24 hour urine samples. 19 different PAHs (including benzo(a)pyrene, pyrene, and phenanthrene) were measured at the workplace by personal air monitoring. The GSTT1 activity in erythrocytes and lymphocyte subpopulations in blood was also measured. Concentrations of phenanthrene, pyrene, and benzo(a)pyrene in air correlated well with the ...
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 ...
Centromere function requires the proper coordination of several subfunctions, such as kinetochore assembly, sister chromatid cohesion, binding of kinetochore microtubules, orientation of sister kinetochores to opposite spindle poles, and their movement towards the spindle poles. Centromere structure appears to be organized in different, separable domains in order to accomplish these functions. Despite the conserved nature of centromere functions, the molecular genetic definition of the DNA sequences that form a centromere in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, in the fruit fly Drosophila melanogaster, and in humans has revealed little conservation at the level of centromere DNA sequences. Also at the protein level few centromere proteins are conserved in all of these four organisms and many are unique to the different organisms. The recent analysis of the centromere structure in the yeast S. pombe by electron microscopy and detailed immunofluorescence microscopy of ...
TY - JOUR. T1 - Evidence that unrejoined DNA double-strand breaks are not predominantly responsible for chromosomal radiosensitivity of AT fibroblasts. AU - Loucas, Bradford. AU - Cornforth, Michael. PY - 2004/11. Y1 - 2004/11. N2 - To examine more fully the nature of chromosomal radiosensitivity in ataxia telangiectasia (AT) cells, we employed 24-color combinatorial painting to visualize 137CS γ-ray-induced chromosome-type aberrations in cells of two AT and one normal primary human fibroblast strains irradiated in log-phase growth. As a measure of misrejoined radiation-induced DSBs, we quantified exchange breakpoints associated with both simple and complex exchanges. As a measure of unrejoined DSBs, we quantified breakpoints from terminal deletions as well as deletions associated with incomplete exchange. For each of these end points, the frequency of damage per unit dose was markedly higher in AT cells compared to normal cells, although the proportion of total breaks that remained unrejoined ...

Analysis of sister-chromatid exchanges and tumorigenicity in cell hybrids | Journal of Cell ScienceAnalysis of sister-chromatid exchanges and tumorigenicity in cell hybrids | Journal of Cell Science

Analysis of sister-chromatid exchanges and tumorigenicity in cell hybrids Message Subject (Your Name) has sent you a message ... The relationship between the spontaneous frequency of sister-chromatid exchanges (SCE) and tumorigenicity was studied in a ...
more infohttp://jcs.biologists.org/content/42/1/117

Sister chromatid exchange analysis in lymphocytes of workers exposed to hexavalent chromium. | Occupational & Environmental...Sister chromatid exchange analysis in lymphocytes of workers exposed to hexavalent chromium. | Occupational & Environmental...

To investigate the usefulness of sister chromatid exchange (SCE) analysis in lymphocytes as an indicator for mutagenic effects ... Sister chromatid exchange analysis in lymphocytes of workers exposed to hexavalent chromium. ... Sister chromatid exchange analysis in lymphocytes of workers exposed to hexavalent chromium. ...
more infohttp://oem.bmj.com/content/46/1/48

DNA single strand breakage, DNA adducts, and sister chromatid exchange in lymphocytes and phenanthrene and pyrene metabolites...DNA single strand breakage, DNA adducts, and sister chromatid exchange in lymphocytes and phenanthrene and pyrene metabolites...

Formation of sister chromatid exchanges (SCE) is a mechanism of repair or bypass of DNA damage during S phase. Although SCE ... Sister chromatid segregation in anaphase of mitosis is initiated through cleavage of cohesin by the protease separase. Two ... The number of sister chromatid exchanges was lower in coke oven workers but this was not significant; thus counting sister ... Home » DNA single strand breakage, DNA adducts, and sister chromatid exchange in lymphocytes and phenanthrene and pyrene ...
more infohttp://connection.ebscohost.com/c/articles/8002898/dna-single-strand-breakage-dna-adducts-sister-chromatid-exchange-lymphocytes-phenanthrene-pyrene-metabolites-urine-coke-oven-workers

Oral History | Life in Science | Scientific Research | Kim Nasmyth on Separase, Cleavage of Cohesion, and Sister Chromatid...Oral History | Life in Science | Scientific Research | Kim Nasmyth on Separase, Cleavage of Cohesion, and Sister Chromatid...

You could not separate sister chromatids without Separase. So we had this model that Separase bound securin. Like in that form ... Oral History -> Life in Science -> Scientific Research -> Kim Nasmyth on Separase, Cleavage of Cohesion, and Sister Chromatid ... Separase, Cleavage of Cohesion, and Sister Chromatid Separation (Kim Nasmyth) Then use your browsers back button to return ... We had meanwhile identified many of the proteins that were directly involved in holding sister chromatids together. And again ...
more infohttp://library.cshl.edu/oralhistory/interview/scientific-experience/scientific-research/nasmyth-separase-cleavage-of-cohesion-and-sister/

Sister chromatid exchange analysis in monitoring chlorambucil therapy in primary nephrotic syndrome of childhood - Semantic...Sister chromatid exchange analysis in monitoring chlorambucil therapy in primary nephrotic syndrome of childhood - Semantic...

Sister chromatid exchange (SCE) analysis is the most sensitive method for assessing chromosome damage induced by chemical ... Sister chromatid exchange analysis in monitoring chlorambucil therapy in primary nephrotic syndrome of childhood. *. A. Y. ... Sister chromatid exchange (SCE) analysis is the most sensitive method for assessing chromosome damage induced by chemical ... article{Elzouki1991SisterCE, title={Sister chromatid exchange analysis in monitoring chlorambucil therapy in primary nephrotic ...
more infohttps://www.semanticscholar.org/paper/Sister-chromatid-exchange-analysis-in-monitoring-c-Elzouki-Al-Nassar/82a0c4f5a482d42079437d47603a721d816b2602

Separase: a universal trigger for sister chromatid disjunction but not chromosome cycle progression. - Oxford NeuroscienceSeparase: a universal trigger for sister chromatid disjunction but not chromosome cycle progression. - Oxford Neuroscience

Destruction of sister chromatid cohesion by Separase may be a universal feature of mitosis in eukaryotic cells. ... In embryonic fibroblasts, Separase depletion blocks sister chromatid separation but does not prevent other aspects of mitosis, ... Separase is a protease whose liberation from its inhibitory chaperone Securin triggers sister chromatid disjunction at anaphase ... Destruction of sister chromatid cohesion by Separase may be a universal feature of mitosis in eukaryotic cells. ...
more infohttps://www.neuroscience.ox.ac.uk/publications/98453

Centromere domain organization and histone modificationsCentromere domain organization and histone modifications

Centromere function requires the proper coordination of several subfunctions, such as kinetochore assembly, sister chromatid ...
more infohttp://sh.diva-portal.org/smash/record.jsf?pid=diva2:508338

To cause genomic instability particularly at chromosome loci that are intrinsically | www.nrtisinhibitor.comTo cause genomic instability particularly at chromosome loci that are intrinsically | www.nrtisinhibitor.com

In addition, we observed that treatment with aphidicolin, a classical drug causing replication stress, induced chromatid breaks ... In addition, we observed that treatment with aphidicolin, a classical drug causing replication stress, induced chromatid breaks ... is designated to describe the recurrent loci that preferentially exhibit chromatid gaps and breaks on metaphase chromosomes ... is designated to describe the recurrent loci that preferentially exhibit chromatid gaps and breaks on metaphase chromosomes ...
more infohttp://www.nrtisinhibitor.com/2017/08/08/to-cause-genomic-instability-particularly-at-chromosome-loci-that-are-intrinsically/

sister chromatid - Everything2.comsister chromatid - Everything2.com

During the anaphase of mitosis and meiosis the sister chromatids are pulled apart by the kinetochore microtubules attached to ... During meiosis, homologous sets of sister chromatids get together to form the tetrad, where they cross over. Again, having the ...
more infohttps://everything2.com/title/sister+chromatid

ChromatidChromatid

A chromatid is one of two identical copies of DNA making up a chromosome that are joined at their centromeres, for the process ... Thus there are 46 chromatids (2xN) Alternatively, a haploid cell with two chromatids per chromosome also has 46 chromatids. ... Thus, there are 23 chromatids (1xN) Etymology. The term chromatid was proposed by McClung (1900) for each of the four threads ... In a cell with 4N chromatids, there are 23 chromosome pairs (46 chromosomes), and each chromosome has 2 chromatids. Thus, there ...
more infohttps://www.bionity.com/en/encyclopedia/Chromatid.html

Meiotic sister chromatid recombination.  - PubMed - NCBIMeiotic sister chromatid recombination. - PubMed - NCBI

Meiotic sister chromatid recombination.. Petes TD1, Pukkila PJ.. Author information. 1. Department of Biology, University of ...
more infohttps://www.ncbi.nlm.nih.gov/pubmed/7484457?dopt=Abstract

Chromosomes, chromatids and chromatin (video) |
Khan AcademyChromosomes, chromatids and chromatin (video) | Khan Academy

Overview of DNA transcription, translation, and replication during mitosis and meiosis. Learn about chromosomes, chromatids, and chromatin.
more infohttps://www.khanacademy.org/science/biology/cellular-molecular-biology/intro-to-cell-division/v/chromosomes-chromatids-chromatin-etc

chromatid (thing) by vivid - Everything2.comchromatid (thing) by vivid - Everything2.com

chromatid (thing). See all of chromatid, there is 1 more in this node. ...
more infohttps://everything2.com/user/vivid/writeups/chromatid

sister chromatid exchange | Schwesterchromatid-Austauschsister chromatid exchange | Schwesterchromatid-Austausch

KudoZ) English to German translation of sister chromatid exchange: Schwesterchromatid-Austausch [alprostadil product ... sister chromatid exchange. Alprostadil showed no evidence of mutagenicity in vitro in the Ames bacterial reverse mutation test ...
more infohttps://www.proz.com/kudoz/english_to_german/medical%3A_pharmaceuticals/1808082-sister_chromatid_exchange.html

Sister chromatids - WikipediaSister chromatids - Wikipedia

A sister chromatid refers to the identical copies (chromatids) formed by the replication of a chromosome, with both copies ... In other words, a sister chromatid may also be said to be one-half of the duplicated chromosome. A pair of sister chromatids ... Biorientation Sister chromatid exchange Kadyk, Lc; Hartwell, Lh (Oct 1992). "Sister chromatids are preferred over homologs as ... There is evidence that, in some species, sister chromatids are the preferred template for DNA repair. Sister chromatid cohesion ...
more infohttps://en.wikipedia.org/wiki/Sister_chromatids

Sister chromatids - WikipediaSister chromatids - Wikipedia

A sister chromatid refers tae the identical copies (chromatids) formed bi the replication o a chromosome, wi baith copies jynt ... Taen frae "https://sco.wikipedia.org/w/index.php?title=Sister_chromatids&oldid=683489" ...
more infohttps://sco.wikipedia.org/wiki/Sister_chromatids

How cohesin ensures sister chromatids segregate correctlyHow cohesin ensures sister chromatids segregate correctly

The protein complex cohesin keeps the sister chromatids together, but how it interacts with the DNA was unknown. A crystal ... In cell division, after replication of the cells chromosomes, the two copies, called sister chromatids, must be kept together ...
more infohttps://www.esrf.eu/home/news/spotlight/content-news/spotlight/spotlight333.html

sister chromatid biorientation | SGDsister chromatid biorientation | SGD

Gene Ontology Term: sister chromatid biorientation. GO ID. GO:0031134 Aspect. Biological Process. Description. The cell cycle ... process in which sister chromatids establish stable attachments to microtubules emanating from opposite spindle poles.. ...
more infohttps://www.yeastgenome.org/go/GO:0031134

meiotic sister chromatid separation | SGDmeiotic sister chromatid separation | SGD

Gene Ontology Term: meiotic sister chromatid separation. GO ID. GO:0051757 Aspect. Biological Process. Description. The process ... meiotic sister chromatid resolution View GO Annotations in other species in AmiGO ... in which sister chromatids are physically detached from each other during meiosis.. Synonyms. ...
more infohttps://www.yeastgenome.org/go/GO:0051757

Exploring mechanics of chromatid cohesionExploring mechanics of chromatid cohesion

Did it also play a part in chromatid cohesion in the worm? Once again, RNA interference showed it did. Finally, if MAU-2 has a ... Exploring mechanics of chromatid cohesion. By PLoS Biology, Jul 5, 2006 - 2:52:37 PM. ... To test whether human MAU-2 had a similar role in linking sister chromatids, the authors used RNA interference to diminish MAU- ... These findings shed light on the mechanics of chromatid cohesion, and will be useful for further elucidating the complex means ...
more infohttp://www.rxpgnews.com/proteins/Exploring_mechanics_of_chromatid_cohesion_4631_printer.shtml

Sister chromatid cohesion and recombination in meiosis.  - PubMed - NCBISister chromatid cohesion and recombination in meiosis. - PubMed - NCBI

Sister chromatids are associated from their formation until their disjunction. Cohesion between sister chromatids is provided ... Recombination, sister chromatid cohesion and the relation between the two processes must be regulated differently in mitosis ... Sister chromatid cohesion and recombination in meiosis.. van Heemst D1, Heyting C. ... Sister chromatid cohesion is intimately linked to other aspects of chromosome behaviour and metabolism, in particular ...
more infohttps://www.ncbi.nlm.nih.gov/pubmed/10855491?dopt=Abstract

Sister-chromatid misbehavior in Drosophila ord mutants. | GeneticsSister-chromatid misbehavior in Drosophila ord mutants. | Genetics

The ord gene product may prevent premature sister-chromatid separation by promoting cohesion of the sister chromatids in a ... Sister-chromatid misbehavior in Drosophila ord mutants.. W Y Miyazaki and T L Orr-Weaver ... Sister-chromatid misbehavior in Drosophila ord mutants.. W Y Miyazaki and T L Orr-Weaver ... Sister-chromatid misbehavior in Drosophila ord mutants.. W Y Miyazaki and T L Orr-Weaver ...
more infohttps://www.genetics.org/content/132/4/1047?ijkey=de4bf3e17a268c06b18af41cf58dc3a0e07006cc&keytype2=tf_ipsecsha

Chromatid - WikipediaChromatid - Wikipedia

Chromatids may be sister or non-sister chromatids. A sister chromatid is either one of the two chromatids of the same ... see articles Sister chromatids and Sister chromatid exchange). Non-sister chromatids, on the other hand, refers to either of ... Sister chromatid exchange (SCE) is the exchange of genetic information between two sister chromatids. SCEs can occur during ... A pair of sister chromatids is called a dyad. Once sister chromatids have separated (during the anaphase of mitosis or the ...
more infohttps://en.wikipedia.org/wiki/Chromatid
  • Sometimes sister chromatids do not separate during cell division, leading to a situation known as nondisjunction where one daughter cell lacks the chromosome while the other gets both copies of it. (wikipedia.org)
  • Sister chromatid differentiation on staining was performed by the FPG technique. (fluoridealert.org)
  • Sister chromatid differentiation (SCD) was achieved in differentiating spermatogonial cells of male Chinese hamsters by the abdominal subcutaneous (sc) implantation of an agar-coated bromode-oxyuridine (BrdUrd) tablet. (springer.com)
  • Here we use the technique of micronucleus (MN) and sister chromatid exchange (SCE) to detect mutagenicity and potential carcinogenicity from fluoride in fluorosis patients who drink elevated concentrations of fluoride in water. (fluoridealert.org)
  • In the September 1st issue of G&D, Drs. Rudra Dubey and Marc Gartenberg (UMDNJ) reveal a surprising new role for tDNAs and RNA polymerase III-associated proteins in sister chromatid cohesion. (eurekalert.org)
  • During the last phases of mitosis , the chromatids separate and move toward opposite poles of the cell . (biology-online.org)