Nucleocytoplasmic transport molecules that bind to the NUCLEAR LOCALIZATION SIGNALS of cytoplasmic molecules destined to be imported into the CELL NUCLEUS. Once attached to their cargo they bind to BETA KARYOPHERINS and are transported through the NUCLEAR PORE COMPLEX. Inside the CELL NUCLEUS alpha karyopherins dissociate from beta karypherins and their cargo. They then form a complex with CELLULAR APOPTOSIS SUSCEPTIBILITY PROTEIN and RAN GTP-BINDING PROTEIN which is exported to the CYTOPLASM.
Short, predominantly basic amino acid sequences identified as nuclear import signals for some proteins. These sequences are believed to interact with specific receptors at the NUCLEAR PORE.
Proteins that form the structure of the NUCLEAR PORE. They are involved in active, facilitated and passive transport of molecules in and out of the CELL NUCLEUS.
Nucleocytoplasmic transport molecules that bind to ALPHA KARYOPHERINS in the CYTOSOL and are involved in transport of molecules through the NUCLEAR PORE COMPLEX. Once inside the CELL NUCLEUS beta karyopherins interact with RAN GTP-BINDING PROTEIN and dissociate from alpha karyopherins. Beta karyopherins bound to RAN GTP-BINDING PROTEIN are then re-transported to the cytoplasm where hydrolysis of the GTP of RAN GTP-BINDING PROTEIN causes release of karyopherin beta.
An opening through the NUCLEAR ENVELOPE formed by the nuclear pore complex which transports nuclear proteins or RNA into or out of the CELL NUCLEUS and which, under some conditions, acts as an ion channel.
A family of proteins involved in NUCLEOCYTOPLASMIC TRANSPORT. Karyopherins are heteromeric molecules composed two major types of components, ALPHA KARYOPHERINS and BETA KARYOPHERINS, that function together to transport molecules through the NUCLEAR PORE COMPLEX. Several other proteins such as RAN GTP BINDING PROTEIN and CELLULAR APOPTOSIS SUSCEPTIBILITY PROTEIN bind to karyopherins and participate in the transport process.
The orderly segregation of CHROMOSOMES during MEIOSIS or MITOSIS.
A genetically related subfamily of RAP GTP-BINDING PROTEINS that share homology with RAS PROTEINS. They bind to Ras effectors but do not activate them, therefore they may antagonize the effects of RAS PROTEINS. This enzyme was formerly listed as EC 3.6.1.47.
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.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
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)
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.
Large multiprotein complexes that bind the centromeres of the chromosomes to the microtubules of the mitotic spindle during metaphase in the cell cycle.
Any method used for determining the location of and relative distances between genes on a chromosome.
A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species.
A microtubule structure that forms during CELL DIVISION. It consists of two SPINDLE POLES, and sets of MICROTUBULES that may include the astral microtubules, the polar microtubules, and the kinetochore microtubules.
Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.
A form of long QT syndrome that is associated with congenital deafness. It is characterized by abnormal cardioelectrophysiology involving the VOLTAGE-GATED POTASSIUM CHANNEL. It results from mutation of KCNQ1 gene (Subtype 1 or JLN1) or the KCNE1 gene (Subtype 2 or JLN2).
Proteins obtained from ESCHERICHIA COLI.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
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).
A post-MORULA preimplantation mammalian embryo that develops from a 32-cell stage into a fluid-filled hollow ball of over a hundred cells. A blastocyst has two distinctive tissues. The outer layer of trophoblasts gives rise to extra-embryonic tissues. The inner cell mass gives rise to the embryonic disc and eventual embryo proper.
Assaying the products of or monitoring various biochemical processes and reactions in an individual cell.
Morphological and physiological development of EMBRYOS.
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.
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.
A microtubule-associated mechanical adenosine triphosphatase, that uses the energy of ATP hydrolysis to move organelles along microtubules toward the plus end of the microtubule. The protein is found in squid axoplasm, optic lobes, and in bovine brain. Bovine kinesin is a heterotetramer composed of two heavy (120 kDa) and two light (62 kDa) chains. EC 3.6.1.-.
The phase of cell nucleus division following METAPHASE, in which the CHROMATIDS separate and migrate to opposite poles of the spindle.
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.
The cell center, consisting of a pair of CENTRIOLES surrounded by a cloud of amorphous material called the pericentriolar region. During interphase, the centrosome nucleates microtubule outgrowth. The centrosome duplicates and, during mitosis, separates to form the two poles of the mitotic spindle (MITOTIC SPINDLE APPARATUS).
A congenital abnormality in which the CEREBRUM is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (Desk Reference for Neuroscience, 2nd ed.)
Anemia characterized by larger than normal erythrocytes, increased mean corpuscular volume (MCV) and increased mean corpuscular hemoglobin (MCH).
Self-replicating, short, fibrous, rod-shaped organelles. Each centriole is a short cylinder containing nine pairs of peripheral microtubules, arranged so as to form the wall of the cylinder.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

In the pre-implantation embryo, aneuploidy resulting from chromosome segregation error is considered responsible for pregnancy loss. However, only a few studies have examined the relationship between chromosome segregation errors during early cleavage and development. Here, we evaluated this relationship by live-cell imaging using the histone H2B-mCherry probe and subsequent single blastocyst transfer using mouse embryos obtained by in vitro fertilization. We showed that some embryos exhibiting early chromosomal segregation error and formation of micronuclei retained their developmental potential; however, the error affected the blastocyst/arrest ratio. Further, single-cell sequencing after live-cell imaging revealed that all embryos exhibiting micronuclei formation during 1st mitosis showed aneuploidy at the 2-cell stage. These results suggest that early chromosome segregation error causing micronuclei formation affects ploidy and development to blastocyst but does not necessarily cause developmental
程金妹.,李建.,汤济鑫.,郝晓霞.,王志鹏.,...&刘以训.(2017).Merotelic Kinetochore Attachment in Oocyte Meiosis II Causes Sister Chromatids Segregation Errors in Aged Mice.Cell Cycle,16(15),1404-1413 ...
This book describes current knowledge about the mechanisms by which cells segregate their already duplicated chromosomes in preparation for cell division. Experts in the field treat several important aspects of this subject: (1) the history of research on mitotic mechanisms, to serve as a background; (2) assembly of the mitotic spindle; (3) Kinetochore assembly and function; (4) the mechanisms of chromosome congression to the metaphase plate; (5) the spindle assembly checkpoint; (6) mechanisms to avoid and correct erroneous chromosome attachments to the spindle; (7) a molecular perspective on spindle assembly in land plants; (8) chromosome segregation in anaphase A; (9) spindle elongation in anaphase B; and (10) the consequences of errors in chromosome segregation. Each chapter provides the reader with a comprehensive and accurate picture of current research in a form that is both readable and authoritative. The volume is suitable for scholars in this and related fields and for teaching at an ...
Many cancers display both structural (s-CIN) and numerical (w-CIN) chromosomal instabilities. Defective chromosome segregation during mitosis has been shown to cause DNA damage that induces structural rearrangements of chromosomes (s-CIN). In contrast, whether DNA damage can disrupt mitotic processes to generate whole chromosomal instability (w-CIN) is unknown. Here we show that activation of the DNA damage response (DDR) during mitosis selectively stabilizes kinetochore-microtubule (k-MT) attachments to chromosomes through Aurora-A and Plk1 kinases, thereby increasing the frequency of lagging chromosomes during anaphase. Inhibition of DDR proteins, ATM or Chk2, abolishes the effect of DNA damage on k-MTs and chromosome segregation, whereas activation of the DDR in the absence of DNA damage is sufficient to induce chromosome segregation errors. Finally, inhibiting the DDR during mitosis in cancer cells with persistent DNA damage suppresses inherent chromosome segregation defects. Thus, DDR ...
In most bacteria two vital processes of the cell cycle: DNA replication and chromosome segregation overlap temporally. The action of replication machinery in a fixed location in the cell leads to the duplication of oriC regions, their rapid separation to the opposite halves of the cell and the duplicated chromosomes gradually moving to the same locations prior to cell division. Numerous proteins are implicated in co-replicational DNA segregation and they will be characterized in this review. The proteins SeqA, SMC/MukB, MinCDE, MreB/Mbl, RacA, FtsK/SpoIIIE playing different roles in bacterial cells are also involved in chromosome segregation. The chromosomally encoded ParAB homologs of active partitioning proteins of low-copy number plasmids are also players, not always indispensable, in the segregation of bacterial chromosomes ...
Studies of chromosome organization in bacterial cells show that the chromosome is an exquisitely organized and dynamic structure (reviewed recently in Thanbichler et al., 2005). Chromosome segregation in bacteria does not occur all at once but in sequential phases (Lau et al., 2003; Viollier et al., 2004; Bates and Kleckner, 2005; Nielsen et al., 2006). After replication at mid-cell, the origin region (oriC) is rapidly segregated outward. The speed at which this occurs (reviewed in Gordon and Wright, 2000) rules out passive models for bacterial chromosome segregation, which proposed that outward cellular growth could drive the movement of a fixed chromosome. As the loci of the chromosome are replicated, they are moved outward to the poles in a sequential fashion (Lau et al., 2003; Viollier et al., 2004; Bates and Kleckner, 2005; Nielsen et al., 2006). In Escherichia coli, there may be a period of sister chromosome cohesion between duplication and subsequent segregation, although its length is ...
The improper partitioning of chromosomes is responsible for a many human maladies. Errors in mitotic chromosome segregation contribute to the development of cancer while errors in meiosis are the leading cause of birth defects and infertility. Proper chromosome segregation requires the co-ordination of chromosome behavior with other cellular events, and the assembly of a functional machine to move the chromosomes to the right place at the right time in the cell cycle. The research in our laboratory is focused on both the regulatory and mechanical aspects of chromosome behavior. Our projects primarily use the yeast, Saccharomyces cerevisiae, as a model to elucidate conserved aspects of eukaryotic chromosome biology. Our goal is to elucidate fundamentals of chromosome behavior that will provide insights into the origins of chromosome segregation errors in humans.. Our laboratory is involved in two major projects. Slk19 is a bi-functional protein. Slk19 is a member of the FEAR signaling pathway ...
Mitotic chromosome malsegregation produces aneuploidy and genome instability. An increasing number of studies have shown that abnormalities such as aneuploidy and whole-chromosome loss of heterozygosity are commonly present in tumor cells. This suggests that chromosome instability and aneuploidy may play a critical role in tumor development and progression ( Sen, 2000).. The integrity of the cell and of its genome and the correct accomplishment of cellular processes depend on the existence of control points in the cell cycle. These control mechanisms, called `checkpoints, inhibit the transition to the next cell cycle phase if the events of the previous phase have not been correctly executed. A mitotic checkpoint has been identified that controls the metaphase to anaphase transition. A large number of studies have demonstrated that in vertebrates the kinetochore plays an active role in the mitotic checkpoint pathway and that microtubule accumulation at the kinetochore and/or tension that ...
Growth and development are dependent on the faithful duplication of cells. Duplication requires accurate genome replication, the repair of any DNA damage, and the precise segregation of chromosomes at mitosis; molecular checkpoints ensure the proper progression and fidelity of each stage. Loss of an …
Research done in Prof. Sharon Bickels lab has demonstrated that oxidative damage causes a premature loss of sister chromatid cohesion and an increase in chromosome segregation errors in Drosophila oocytes during meiosis. In women, the probability of miscarriage or Down Syndrome increases dramatically with age. Studies of maternal age effect indicate that errors in female meiosis contribute significantly to this age-related effect. The research done by the Bickel lab demonstrates that if oxidative damage contributes to maternal age effect then reducing oxidative damage could be a strategy for reducing chromosome segregation errors during meiosis.. Professor Sharon Bickel, MCB graduate student Adrienne Perkins, Class of 2013 undergraduate researcher Thomas Das and second year MCB graduate student Lauren Panzera contributed to this work. These findings were published in the Proceeding of the National Academy of Sciences: http://www.pnas.org/content/early/2016/10/12/1612047113.full ...
Cells possessing the incorrect number of chromosomes (referred to as aneuploid) can arise as a result of chromosome mis-segregation. Prevention of aneuploidy is especially important in germ cells, as these cells pass genetic information to the next generation, but also in pluripotent cells as these give rise to all tissues and cells of the offspring, including germ cells. Aneuploid conceptions have a detrimental effect on pregnancy outcomes, are surprisingly common in humans (estimated 10-30%), and are a leading cause of miscarriage and developmental disorders. In both meiosis and mitosis, accurate chromosome segregation relies on the correct orientation of sister chromatids during metaphase, which ensures bipolar spindle attachment. Newly replicated sister chromatids are able to align properly on the spindle due to cohesion holding them together. The protein complex responsible for sister chromatid cohesion (SCC) is called cohesin, and has specific subunits depending on its particular role. The ...
Cell cycle: a series of events that occur in cells leading up to their division and replication. Its divided into two main parts, Interphase and a Mitotic or M phase. Interphase is further subdivided into three phases including: G1, S and G2. Each phase has different events occurring within them Cell division: an essential process that occurs in almost all living things. It is characterised by the separation of a cell into two daughter cells. In metazoans, it involves separation of the nucleus and of the cytoplasm Centromere: Confined portion of a mitotic chromosome where sister chromatids are attached and from which kinetochore fibers extend toward a spindle pole. It is essential for correct chromosome segregation during mitosis Chromatin:it is made up of histones, non-histone proteins and DNA which condenses to form eukaryotic chromosomes Chromosome: a single molecule of DNA which is highly organised and tightly packed around proteins (histones) Chromosomal segregation: process by which ...
Cell cycle: a series of events that occur in cells leading up to their division and replication. Its divided into two main parts, Interphase and a Mitotic or M phase. Interphase is further subdivided into three phases including: G1, S and G2. Each phase has different events occurring within them Cell division: an essential process that occurs in almost all living things. It is characterised by the separation of a cell into two daughter cells. In metazoans, it involves separation of the nucleus and of the cytoplasm Centromere: Confined portion of a mitotic chromosome where sister chromatids are attached and from which kinetochore fibers extend toward a spindle pole. It is essential for correct chromosome segregation during mitosis Chromatin:it is made up of histones, non-histone proteins and DNA which condenses to form eukaryotic chromosomes Chromosome: a single molecule of DNA which is highly organised and tightly packed around proteins (histones) Chromosomal segregation: process by which ...
The spindle assembly checkpoint (SAC) prevents chromosome missegregation by coupling anaphase onset with correct chromosome attachment and tension to microtubules. It does this by generating a diffusible signal from free kinetochores into the cytoplasm, inhibiting the anaphase-promoting complex (APC). The volume in which this signal remains effective is unknown. This raises the possibility that cell volume may be the reason the SAC is weak, and chromosome segregation error-prone, in mammalian oocytes. Here, by a process of serial bisection, we analyzed the influence of oocyte volume on the ability of the SAC to inhibit bivalent segregation in meiosis I. We were able to generate oocytes with cytoplasmic volumes reduced by 86% and observed changes in APC activity consistent with increased SAC control. However, bivalent biorientation remained uncoupled from APC activity, leading to error-prone chromosome segregation. We conclude that volume is one factor contributing to SAC weakness in oocytes. ...
Whitehead Institute researchers have determined the organization of a protein complex that is critical during chromosome segregation. Without the solid foundation supplied by this complex, which is called the Constitutive Centromere-Associated Network, the link between chromosome and kinetochore would fail, as would chromosome segregation and cell division.
Chromosome segregation and cell division are essential, highly ordered processes that depend on numerous protein complexes. Results from recent RNA interference screens indicate that the identity and composition of these protein complexes is incompletely understood. Using gene tagging on bacterial artificial chromosomes, protein localization, and tandem-affinity purification-mass spectrometry, the MitoCheck consortium has analyzed about 100 human protein complexes, many of which had not or had only incompletely been characterized. This work has led to the discovery of previously unknown, evolutionarily conserved subunits of the anaphase-promoting complex and the gamma-tubulin ring complex--large complexes that are essential for spindle assembly and chromosome segregation. The approaches we describe here are generally applicable to high-throughput follow-up analyses of phenotypic screens in mammalian cells ...
TY - BOOK ID - 21915 TI - Mechanisms of Mitotic Chromosome Segregation AU - J. Richard McIntosh PY - 2017 SN - 9783038424031 9783038424024 DB - DOAB KW - chromosome segregation, microtubule dynamics, kinetochore, centrosome, genome stability, Cell division, Cell cycle, Cell reproduction, Checkpoints, Cell motility, Inheritance, Microtubules, Cytoskeleton, Cell regulation, Down Syndrome, Trisomies UR - https://www.doabooks.org/doab?func=search&query=rid:21915 AB - This book describes current knowledge about the mechanisms by which cells segregate their already duplicated chromosomes in preparation for cell division. Experts in the field treat several important aspects of this subject: (1) the history of research on mitotic mechanisms, to serve as a background; (2) assembly of the mitotic spindle; (3) Kinetochore assembly and function; (4) the mechanisms of chromosome congression to the metaphase plate; (5) the spindle assembly checkpoint; (6) mechanisms to avoid and correct erroneous chromosome ...
Many cancers have extremely high rates of chromosomal instability (CIN). Some cancers have chromosome segregation errors in every cell division, which would be detrimental to the growth of normal cells. Little is known about how cancers are able to thrive with high levels of CIN. We aim to determine how cells evolve to cope with CIN by creating a model system for persistent chromosomal instability in budding yeast. What types of mutations allow cells to adapt to a constantly shifting genomic content? What are the direct effects of CIN and aneuploidy on the health and viability of cells?. ...
Chromosomes must establish stable biorientation prior to anaphase to achieve faithful segregation during cell division. The detailed process by which chromosomes are bioriented and how biorientation is coordinated with spindle assembly and chromosome congression remain unclear. Here, we provide comp …
The research interests of the participating groups are listed below. Follow the links for more detailed information.. Gustav Ammerer: Signal transduction and transcriptional regulation in yeast. Oliver Bell: Editing the epigenome: plasticity and memory of chromatin structure. Frederic Berger: Histone variants in chromatin structure. Christopher Campbell: Chromosome dynamics. Alexander Dammermann: Centriole assembly and function. Daniel Gerlich: Cytoskeletal and membrane dynamics in cell division. Juraj Gregan: Chromosome segregation during mitosis and meiosis. Verena Jantsch-Plunger: Faithful chromosome segregation in C. elegans meiosis. Franz Klein: Deconstructing the meiotic (yeast) chromosome. Josef Loidl: Meiotic chromosome pairing and recombination. Ortrun Mittelsten Scheid: Epigenetic changes in plants ...
Control of sister chromatid cohesion/separation is critical to ensure faithful chromosome segregation during mitosis and meiosis. Failures in this mechanism during mitosis often lead to aneuploidy and chromosome instability, a major cause of cancer, while failures during meiosis promote miscarriage, birth defects, and infertility in humans. A key protagonist in this control is the cohesin complex, which are composed essentially by four subunits, two of them, called Smc1 and Smc3 (Structural maintenance of chromosomes), are members of a highly conserved protein family also found in prokaryotes and are implicated in various functions related to DNA dynamics, dose compensation, chromosome condensation, recombination, etc. The other two subunits are specific to eukaryotes and, depending on the organism, are termed Scc1/Rad21 or Scc3/STAG, the former mainly for yeast and the latter in higher eukaryotes. In addition to their function in chromatid cohesion during chromosome segregation, our previous ...
DNA replication, transcription, repair, epigenetic inheritance, and chromosome segregation are all processes critical for maintaining cellular viability. In euk...
Author: Hutchins, J. R. A. et al.; Genre: Journal Article; Published in Print: 2010-04-30; Title: Systematic analysis of human protein complexes identifies chromosome segregation proteins.
STUDY QUESTION Are the kinase feedback loops that regulate activation and centromeric targeting of the chromosomal passenger complex (CPC), functional during mitosis in human embryos? SUMMARY ANSWER Investigation of the regulatory kinase pathways involved in centromeric CPC targeting revealed normal phosphorylation dynamics of histone H2A at T120 (H2ApT120) by Bub1 kinase and subsequent recruitment of Shugoshin, but phosphorylation of histone H3 at threonine 3 (H3pT3) by Haspin failed to show the expected centromeric enrichment on metaphase chromosomes in the zygote. WHAT IS KNOWN ALREADY Human cleavage stage embryos show high levels of chromosomal instability. What causes this high error rate is unknown, as mechanisms used to ensure proper chromosome segregation in mammalian embryos are poorly described. STUDY DESIGN, SIZE, DURATION In this study, we investigated the pathways regulating CPC targeting to the inner centromere in human embryos. We characterized the distribution of the CPC in ...
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 ...
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Mutations in CDCA7 and HELLS that respectively encode a CXXC-type zinc finger protein and an SNF2 family chromatin remodeler cause immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome types 3 and 4. Here, we demonstrate that the classical nonhomologous end joining (C-NHEJ) proteins Ku80 and Ku70, as well as HELLS, coimmunoprecipitated with CDCA7. The coimmunoprecipitation of the repair proteins was sensitive to nuclease treatment and an ICF3 mutation in CDCA7 that impairs its chromatin binding. The functional importance of these interactions was strongly suggested by the compromised C-NHEJ activity and significant delay in Ku80 accumulation at DNA damage sites in CDCA7- and HELLS-deficient HEK293 cells. Consistent with the repair defect, these cells displayed increased apoptosis, abnormal chromosome segregation, aneuploidy, centrosome amplification, and significant accumulation of γH2AX signals. Although less prominent, cells with mutations in the other ICF genes ...
Mutations in CDCA7 and HELLS that respectively encode a CXXC-type zinc finger protein and an SNF2 family chromatin remodeler cause immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome types 3 and 4. Here, we demonstrate that the classical nonhomologous end joining (C-NHEJ) proteins Ku80 and Ku70, as well as HELLS, coimmunoprecipitated with CDCA7. The coimmunoprecipitation of the repair proteins was sensitive to nuclease treatment and an ICF3 mutation in CDCA7 that impairs its chromatin binding. The functional importance of these interactions was strongly suggested by the compromised C-NHEJ activity and significant delay in Ku80 accumulation at DNA damage sites in CDCA7- and HELLS-deficient HEK293 cells. Consistent with the repair defect, these cells displayed increased apoptosis, abnormal chromosome segregation, aneuploidy, centrosome amplification, and significant accumulation of γH2AX signals. Although less prominent, cells with mutations in the other ICF genes ...
Mutations in CDCA7 and HELLS that respectively encode a CXXC-type zinc finger protein and an SNF2 family chromatin remodeler cause immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome types 3 and 4. Here, we demonstrate that the classical nonhomologous end joining (C-NHEJ) proteins Ku80 and Ku70, as well as HELLS, coimmunoprecipitated with CDCA7. The coimmunoprecipitation of the repair proteins was sensitive to nuclease treatment and an ICF3 mutation in CDCA7 that impairs its chromatin binding. The functional importance of these interactions was strongly suggested by the compromised C-NHEJ activity and significant delay in Ku80 accumulation at DNA damage sites in CDCA7- and HELLS-deficient HEK293 cells. Consistent with the repair defect, these cells displayed increased apoptosis, abnormal chromosome segregation, aneuploidy, centrosome amplification, and significant accumulation of γH2AX signals. Although less prominent, cells with mutations in the other ICF genes ...
MIT biologists have discovered that the environment surrounding a cell plays an integral role in its ability to accurately segregate its chromosomes.
Chromosome segregation during male meiosis is tailored to rapidly generate multitudes of sperm. Little is known about mechanisms that efficiently partition chromosomes to produce sperm. Using live imaging and tomographic reconstructions of spermatocyte meiotic spindles inCaenorhabditis elegans, we find the lagging X chromosome, a distinctive feature of anaphase I inC. elegans males, is due to lack...
early embryonic: 3/5 embryos show spindle related defects, in one of the cases the spindle is hardly visible, in others centration fails or is inaccurate, rocking is missing. This leads to chromosome segregation defects in two of the embryos ...
In a body, every single cell has the same number of chromosomes. This is because when a cell divides, the replicated chromatids are equally segregated into daughter cells. But, the first meiotic division is a clear exception. This division segregates maternal and paternal chromosomes for production of eggs and sperms, which are the origin of a new life. What is the story behind this division?. Read More ...
If you have a question about this talk, please contact Ross Waller.. Host: Mark Carrington. Abstract not available. This talk is part of the Parasitology Seminars series.. ...
An intricate network of proteins ensures the faithful transmission of genetic information through cell generations. The Structural Maintenance of Chromosomes (SMC) protein complex family plays a pivotal role in maintaining genome stability. Initially, the three eukaryotic SMC complexes, cohesin, condensin and Smc5/6 complex (Smc5/6) were identified for their functions in chromosome cohesion, condensation and recombination. Later, it was shown that SMC complexes also control replication and transcription. Another important group of proteins involved in the maintenance of genome stability are the topoisomerases. These enzymes control DNA topology to ensure faithful replication, transcription and chromosome segregation ...
Michael Goldberg is a Professor in the Department of Molecular Biology and Genetics. Dr. Goldberg is a member of the Graduate Field of Genetics, Genomics and Development and the Graduate Field of Biochemistry, Molecular, and Cell Biology. The Goldberg lab studies the molecular mechanisms which ensure accurate chromosome segregation and other chromosome behaviors.
NIMA in A. nidulans has known functions in G2-M checkpoint control, as does at least one of its mammalian orthologs, Nek2. Nek2 phosphorylates the kinetochore-associated mitotic regulator protein Hec1 and is therefore crucial for faithful chromosome segregation to daughter cells (13) . Our data suggest that Nek1 may be important for sensing, responding to, or repairing DNA damage and thereby for regulating apoptosis and cellular proliferation after injury. When Nek1 is mutated or when its up-regulation is otherwise insufficient, cells are more likely to die aberrantly or fail to proliferate when they normally should. Some cells surviving the insult would also be more likely to pass subtle mutations on to their daughters, which could then accumulate activating oncogenic or inactivating tumor suppressor mutations. Up-regulation of Nek1 may be a defensive response to cellular and DNA injury, a response to prevent excessive or unscheduled apoptosis. If so, we predict that Nek1 might be overexpressed ...
Classical simulations are described of the fully relaxed surface lattice structures of the five lowest-index planes of α-Al20 3 and the resulting crystal morphology. The surface coverage by yttrium and magnesium as a function of temperature is evaluated on the basis of a non-Arrhenius isotherm and calculated heats of surface segregation. The calculated morphology, surface coverages and heats of segregation are compared with experiment. A quantum simulation of a relaxed {0001} surface is presented and the surface structure and energy compared with the classical results. Estimates are made of the adsorption energy of HF at the {0001} surface. ...
Diagnostic screening allows medical practitioners to identify diseases caused by defective chromosomes, genes or proteins. This screening can occur pre-natally (before birth), pre-symptomatically (before symptoms develop) or be used to confirm a suspected diagnosis. ...
early embryonic: Very reproducible, robust phenotype. Pronuclei and nuclei are smaller or barely visible. Interaction between pronuclei can be impaired, spindle is thin and tends to bend during rocking and elongation in P0. This results in chromosome mis-segregation (leading to karyomeres), or even absence of spindle, and furrow regression at cytokinesis. Beautiful ...
This spindle has a few problems because a number of chromosomes are attached to only one of the spindle poles. These types of attachments are dangerous because they will lead to mis-segregation of the genome during cell division.. ...
Self-Placing Concrete segregation set of tests - Béton Auto-Plaçant ensemble dessais de ségrégation (). The Forney Column Segregation Test Set contains everything needed to determine the potential segregation of coarse aggregate in SCC mixtures tes
Supplementary MaterialsSupplementary Information 41467_2020_16997_MOESM1_ESM. genome cancer and instability. locus on chromosome XV17. Significantly, this system actions frequencies of noncrossover (NCO) and CO in DSB restoration, and in addition distinguishes between brief and long-tract GC (Fig.?1a; Supplementary Fig.?1). Upon I-gene and segregation: white (and deletion was proven to boost DSB-induced chromosome reduction occasions inside a different hereditary program, because of abortive BIR occasions14 possibly. To verify if the alteration from the HR restoration might be due to early chromosome segregation in deletion seriously affected BIR, from the cell-cycle stage irrespective, confirming our earlier observation how the BIR defect of will be faulty in BIR for yet another reason than lacking signalling to Pif1. Open up in another windowpane Fig. 2 Rad9 promotes DSB repair through BIR.a Scheme of the genetic system to test BIR in JRL092 background. b Southern blot of deletion increased ...
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Most people have a passing knowledge of the food they eat, and perhaps how it gets digested. As with all human body systems, however, details of the digestive or gastrointestinal (GI) tract-including the incredibly rich microbial flora found at the last portion of the small intestine and the entire large intestine-are an amazing testimony to creation.. Indeed, on a given day the bacterial population within the human colon usually doubles at least once. This means the common Escherichia coli (E. coli) must replicate (duplicate) its circular chromosome in just 20 short minutes.. The replication of millions of base pairs of DNA is a daunting task in such a small area. The E. coli chromosome must spin at the equivalent of 300 revolutions per second as it makes a second chromosome for upcoming cell division.. A host of unique and diverse bacteria inhabit the large intestine-over 400 bacterial species-and most of them are anaerobic (living in the absence of free oxygen) and are concerned with the ...
Errors in chromosome segregation in mammalian oocytes lead to aneuploid eggs that are developmentally compromised. In mitotic cells, mitotic centromere associated kinesin (MCAK; KIF2C) prevents chromosome segregation errors by detaching incorrect microtubule-kinetochore interactions. Here, we examine whether MCAK is involved in spindle function in mouse oocyte meiosis I, and whether MCAK is necessary to prevent chromosome segregation errors. We find that MCAK is recruited to centromeres, kinetochores and chromosome arms in mid-meiosis I, and that MCAK depletion, or inhibition using a dominant-negative construct, causes chromosome misalignment. However, the majority of oocytes complete meiosis I and the resulting eggs retain the correct number of chromosomes. Moreover, MCAK-depleted oocytes can recover from mono-orientation of homologous kinetochores in mid-meiosis I to segregate chromosomes correctly. Thus, MCAK contributes to chromosome alignment in meiosis I, but is not necessary for ...
Heterochromatin protein 1 is associated with centromeric heterochromatin in Drosophila, mice, and humans. Loss of function mutations in the gene encoding heterochromatin protein 1 in Drosophila, Suppressor of variegation2-5, decrease the mosaic repression observed for euchromatic genes that have been juxtaposed to centromeric heterochromatin. These heterochromatin protein 1 mutations not only suppress this position-effect variegation, but also cause recessive embryonic lethality. In this study, we analyze the latter phenotype in the hope of gaining insight into heterochromatin function. In our analyses of four alleles of Suppressor of variegation2-5, the lethality was found to be associated with defects in chromosome morphology and segregation. While some of these defects are seen throughout embryonic development, both the frequency and severity of the defects are greatest between cycles 10 and 14 when zygotic transcription of the Suppressor of variegation2-5 gene apparently begins. By this time ...
Lagging chromosomes during anaphase are an easily assayed and therefore commonly reported mitotic defect. However, in most cases, the mechanisms that give rise to lagging chromosomes are unknown. Lagging chromosomes can be caused by asbestos fibers (Hersterberg and Barrett, 1985), elevated ras p21 expression (Hagag et al., 1990), carcinogens such as diethylstilbestrol (Schiffmann and De Boni, 1991), and inherited genetic conditions such as Roberts syndrome (Jabs et al., 1991). Chromosomes, chromatids, and chromosome fragments that do not segregate properly often end up spatially separated from the bulk of the chromosomes and will reform a separate nuclear envelope after mitosis is completed. This results in a cell containing micronuclei. Sometimes these cells are described as multinucleate. Severe chromosome segregation defects will in turn inhibit cytokinesis giving rise to truly multinucleate cells (Schultz and Onfelt, 1994). The mechanism by which these diverse agents disrupt anaphase ...
Accurate segregation of meiotic chromosomes requires that sister-chromatids remain physically associated from the time of their synthesis during S phase until they segregate toward opposite poles at anaphase II. In Drosophila melanogaster meiosis, physical association of sister chromatids, known as sister-chromatid cohesion, requires the protein product of the orientation disruptor (ord) gene. Genetic and cytological analyses of ord mutants indicate that sister chromatids separate precociously in the absence of ORD activity, resulting in random chromosome segregation during both meiotic divisions. To understand the molecular basis of ORD activity more fully, we localized ORD protein in Drosophila spermatocytes using immunofluorescence and demonstrate that ORD associates with centromeres of meiotic chromosomes from early G2 through anaphase II. Maintenance of ORD at centromeres until anaphase II requires functional MEI-S332 protein, as centromeric ORD signal disappears during anaphase I in ...
The IPL1 gene is required for high-fidelity chromosome segregation in the budding yeast Saccharomyces cerevisiae. Conditional ipl1ts mutants missegregate chromosomes severely at 37 degrees C. Here, we report that IPL1 encodes an essential putative protein kinase whose function is required during the later part of each cell cycle. At 26 degrees C, the permissive growth temperature, ipl1 mutant cells are defective in the recovery from a transient G2/M-phase arrest caused by the antimicrotubule drug nocodazole. In an effort to identify additional gene products that participate with the Ipl1 protein kinase in regulating chromosome segregation in yeast, a truncated version of the previously identified DIS2S1/GLC7 gene was isolated as a dosage-dependent suppressor of ipl1ts mutations. DIS2S1/GLC7 is predicted to encode a catalytic subunit (PP1C) of type 1 protein phosphatase. Overexpression of the full-length DIS2S1/GLC7 gene results in chromosome missegregation in wild-type cells and exacerbates the ...
Microtubules segregate chromosomes by attaching to macromolecular kinetochores. Only microtubule-end attached kinetochores can be pulled apart; how these end-on attachments are selectively recognised and stabilised is not known. Using the kinetochore and microtubule-associated protein, Astrin, as a molecular probe, we show that end-on attachments are rapidly stabilised by spatially-restricted delivery of PP1 near the C-terminus of Ndc80, a core kinetochore-microtubule linker. PP1 is delivered by the evolutionarily conserved tail of Astrin and this promotes Astrins own enrichment creating a highly-responsive positive feedback, independent of biorientation. Abrogating Astrin:PP1-delivery disrupts attachment stability, which is not rescued by inhibiting Aurora-B, an attachment destabiliser, but is reversed by artificially tethering PP1 near the C-terminus of Ndc80. Constitutive Astrin:PP1-delivery disrupts chromosome congression and segregation, revealing a dynamic mechanism for stabilising ...
Mitosis is a key event in the life of a cell, where duplicated chromosomes are separated into the daughter cells. Defects associated with chromosome segregation can lead to aneuploidy, a hallmark of cancer. Chromosome segregation is achieved by the mitotic spindle, which is composed of microtubules (MTs), motors and microtubule associated protein (MAPs). Motors such as kinesins generate forces within the spindle while MAPs perform functions such as organize the spindle pole and maintain the bipolar spindle. Both motors and MAPs contribute to spindle mechanics. Here I used the relatively simple fission yeast to address how defects in spindle mechanics affect chromosome segregation. The metaphase spindle is maintained at a constant length by an antagonistic force-balance model yet how the regulation of metaphase spindle length contribute to subsequent chromosome segregation remains unexplored. To test the force-balance model, I applied gene deletion and fast microfluidic temperature-control with live-cell
Accurate chromosome segregation in mitosis is required to maintain genetic stability. hZwint-1 [human Zw10 (Zeste white 10)-interacting protein 1] is a kinetochore protein known to interact with the kinetochore checkpoint protein hZw10. hZw10, along with its partners Rod (Roughdeal) and hZwilch, form a complex which recruits dynein-dynactin and Mad1-Mad2 complexes to the kinetochore and are essential components of the mitotic checkpoint. hZwint-1 localizes to the kinetochore in prophase, before hZw10 localization, and remains at the kinetochore until anaphase, after hZw10 has dissociated. This difference in localization timing may reflect a role for hZwint-1 as a structural kinetochore protein. In addition to hZw10, we have found that hZwint-1 interacts with components of the conserved Ndc80 and Mis12 complexes in yeast two-hybrid and GST (glutathione transferase) pull-down assays. Furthermore, hZwint-1 was found to have stable FRAP (fluorescence recovery after photobleaching) dynamics similar ...
In humans, early embryo development is a complex process that consists of sequential events: oocyte maturation, fertilization, embryonic growth and implantation. Disruption of these highly regulated processes results in reproductive failure and infertility. This study characterizes and describes embryonic aneuploidy, mitochondrial content level and endometrial microbial environment related to reproductive competence, in particular instances in which failure results. To examine the molecular underpinnings of mammalian gamete and early embryo chromosome segregation, we established a comprehensive chromosomal screening (CCS) method for mice poly bodies, oocytes and embryos by the application of whole genome amplification (WGA) and next generation sequencing (NGS). First, we validated this approach using single mouse embryonic fibroblasts engineered to have stable trisomy 16. We further validated this method by identifying reciprocal chromosome segregation errors in the products of meiosis I (gamete and
Looking for chromosome congression? Find out information about chromosome congression. congression Explanation of chromosome congression
It will be capable of destabilising defective non-bipolar attachments and as this kind of functions as an errorcorrection component that assures faithful segregation of sister chromatids. Merotelic chromosome attachments Merotely is surely an attachment state during which a single kinetochore attaches to microtubules from each poles. Merotelic attachments happen usually in early mitosis and when left uncorrected they induce anaphase lagging chromosomes and may lead to aneuploidy . The vast majority of merotelic attachments are resolved in prometaphase and latest scientific studies identified a serious function for Aurora-B in this correction operation. Aurora-B gets enriched at centromeres of merotelically attached kinetochores wherever it promotes kinetochoremicrotubule turnover more than likely via regulation of MCAK. Aurora-B influences the function of MCAK at several amounts. To start with, Aurora-B action is needed for your concentration of MCAK on centromeres ...
Neoplastic cells are genetically unstable. Strategies that target pathways affecting genome instability can be exploited to disrupt tumor cell growth potentially with limited consequences to normal cells. Chromosomal instability (CIN) is one type of genome instability characterized by mitotic defects that increase the rate of chromosome mis-segregation. CIN is frequently caused by extra centrosomes that transiently disrupt normal bipolar spindle geometry needed for accurate chromosome segregation. Tumor cells survive with extra centrosomes because of biochemical pathways that cluster centrosomes and promote chromosome segregation on bipolar spindles. Recent work shows that targeted inhibition of these pathways prevents centrosome clustering and forces chromosomes to segregate to multiple daughter cells, an event triggering apoptosis that we refer to as anaphase catastrophe. Anaphase catastrophe specifically kills tumor cells with more than two centrosomes. This death program can occur after ...
Aneuploidy is the leading cause of pregnancy loss and birth defects in humans. At least 5% of all recognized pregnancies are aneuploid. Maternal meiosis is especially error-prone and the rate of chromosome missegregation increases exponentially with advancing maternal age. Despite its clinical significance, the mechanisms underlying maternal age-dependent segregation errors are not understood. One hypothesis is that cohesion deteriorates with advancing maternal age and homologous chromosomes that do not maintain chaismata segregate randomly during meiosis. With Drosophila as a model organism, I have used techniques developed in our laboratory to experimentally age oocytes. To accelerate loss of cohesion with age, I utilized mutant flies with slightly compromised meiotic cohesion. A standard genetic test was utilized to assess errors in meiotic chromosome segregation after oocytes were subjected to the aging regimen. My objective was to determine whether aging of oocytes with slightly compromised ...
Egg infertility is a predisposition to miscarriages, infertility, and trisomic pregnancies caused by increased frequency of chromosome segregation errors in the eggs of women of advanced maternal age (AMA). Egg infertility is now a significant public health issue, with 1 in 5 US women now attempting her first pregnancy after age 35. Increased rates of egg infertility temporally coincide with rising levels of FSH that occur with age. By age 42, up to 87% of embryos are aneuploid, and 40-50% of women experience egg infertility. An Introductory Editorial will present an overview of causative factors and potential therapeutic strategies to prevent egg aneuploidy and infertility. Papers in series will be comprised of data drawn from studies performed both in animals and in humans. Part I will discuss endocrine and other molecular changes implicated in the pathogenesis of AMA oocyte aneuploidy and infertility. Section 1 will discuss defects that emerge with age in controlling the fidelity of meiotic oocyte
Many cancers have extremely high rates of chromosomal instability (CIN). Some cancers have chromosome segregation errors in every cell division, which would be detrimental to the growth of normal cells. Little is known about how cancers are able to thrive with high levels of CIN. We aim to determine how cells evolve to cope with CIN by creating a model system for persistent chromosomal instability in budding yeast. What types of mutations allow cells to adapt to a constantly shifting genomic content? What are the direct effects of CIN and aneuploidy on the health and viability of cells? close ...
Meiotic chromosome segregation must occur with high fidelity in order to prevent the generation of deleterious aneuploidies. In meiosis I, homologous chromosomes pair, then migrate to opposite poles of the spindle. This process uses a collection of unique structures and mechanisms that have yet to be thoroughly characterized. To acquire a collection of informative meiotic mutants, we carried out a novel genetic screen in Saccharomyces cerevisiae. This screen was designed to identify dominant mutants in which meiosis I chromosome segregation occurs with decreased fidelity. One mutant recovered using this screen, SID1-1 (sister disjunction), showed an incidence of spores disomic for a marked chromosome III that was 25-fold greater than the wild-type level. Crossing-over is slightly, but not dramatically, reduced in SID1-1. Both recombinant and nonrecombinant chromosomes segregate with reduced fidelity in the presence of SID1-1. We present evidence that the mutant is defective in sister-chromatid ...
Meiosis is the process of specialized divisions that produce haploid gametes from diploid cells. Meiotic chromosome distribution is a critical event in sexual reproduction. Failure of chromosome segregation during meiosis results in progeny that are aneuploid, possessing chromosomes above or below the 2N number of the diploid genome. Such failures have many important consequences, not least of which is the high rate of aneuploid oocyte production in mammals, a central cause of human infertility, miscarriages, and birth defects (Bennabi et al., 2016). Beaven et al. examined the role of Drosophila melanogaster 14-3-3 proteins in meiotic chromosome segregation and found that they promote accurate assembly of meiotic spindles through spatial regulation of claret nondisjunctional (Ncd), a minus end-directed kinesin-14 family motor protein that mediates sliding of antiparallel microtubules and cross-links parallel microtubules (Fink et al., 2009). This inhibition is relieved locally through ...
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Here, we found that SphK1 and its product S1P regulate mitosis. SphK1 promoted proper mitotic progression in a SAC-dependent manner, whereas increased SphK1 activity accelerated mitosis (Movie S1 and Movie S2). S1P overrode the mitotic spindle checkpoint, led to premature mitotic exit, and induced chromosome segregation defects through a pathway involving S1P5 and phosphatidylinositol 3-kinase (PI3K)-AKT signaling that was at least partially mediated by Polo-like kinase 1 (PLK1).. In summary, our study uncovers a previously unknown role for SphK1-S1P-S1P5 signaling in controlling proper mitotic progression through prometaphase to the metaphase-to-anaphase transition. More generally, our findings support the concept that cellular micro- environment plays an important role in coordination of mitosis and paves the way for future studies evaluating the relationship between extracellular signals, mitotic progression, and chromosomal stability.. ...
Altered expressions and/or mutations of cell cycle regulators result in the development of cancer (1 , 34) . Disruption of mitotic checkpoints can result in abnormal nuclei, missegregated chromosomes, and aneuploidy (35 , 36) . Among the most notable abnormalities commonly found in tumor cells are chromosomal rearrangements and changes in chromosome number (4, 5, 6) . This property of cancer cells is important, especially for our understanding of the regulatory mechanisms that control the progression of malignancy. In colorectal tumors without microsatellite instability, for example, a defect in chromosome segregation results in gains or losses in excess of 10− 2/chromosome/segregation (6) . Although the precise mechanisms by which duplicated chromosomes are equally segregated during mitosis are largely unknown, the centrosome is believed to play an important role(s) in the formation of bipolar spindles. Mutations in fly aurora and yeast IPL1 are responsible for a chromosomal segregation ...
Chromosomes, which are the vehicles of genetic heredity, have to be duplicated in S-phase and equally segregated into daughter cells during M-phase in the cell cycle progression. One of crucial factors, which ensure the accurate chromosome segregation, is the kinetochore that is a large protein complex assembled on the centromere of each chromosome. The kinetochore binds to spindle microtubules and connects with chromosomes. Defects in the kinetochore results in chromosome missegregation, leading to aneuploidy that causes genetic disorders including cancer. Therefore, understanding of structure and function of the kinetochore is important not only for preventing from the genetic disorders but also for answering a fundamental biological question how are chromosomes accurately segregated ...
Defective segregation of chromosomes during cell division causes aneuploidy and is a characteristic feature of cancer cells. Cells therefore utilize multiple mechanisms to ensure faithful segregation and prevent aneuploidy, including phospho-regulation of proteins responsible for separating replicated chromosomes during mitosis. These mechanisms depend on the essential, conserved protein kinase Mps1. The goal of my work is to identify the downstream effectors of Mps1 in chromosome segregation and to illuminate the mechanisms of Mps1 function. This work will combine novel biochemical and cell biological approaches with emerging structural analysis methods to improve fundamental understanding of phospho-regulation of chromosome segregation.. ...
Protein kinase which plays an important role in mitotic cell cycle progression. Required for chromosome segregation at metaphase-anaphase transition, robust mitotic spindle formation and cytokinesis. Phosphorylates ATF4, CIR1, PTN, RAD26L, RBBP6, RPS7, RPS6KB1, TRIP4, STAT3 and histones H1 and H3. Phosphorylates KIF11 to promote mitotic spindle formation. Involved in G2/M phase cell cycle arrest induced by DNA damage. Inhibition of activity results in apoptosis. May contribute to tumorigenesis by suppressing p53/TP53-induced cancer cell senescence ...
Tight regulation of histone relative stoichiometry and overall levels is fundamental to the preservation of genome integrity in all eukaryotes. Abnormal histone levels induce defects in mitotic chromosome segregation, chromatin structure, and transcription and lead to loss of viability (Meeks-Wagner and Hartwell 1986; Han et al. 1987; Clark-Adams et al. 1988; Kim et al. 1988; Norris et al. 1988). Defects in chromatin structure caused by inactivation of nucleosome assembly factors cause high rates of chromosomal rearrangements and spontaneous DNA damage and elicit checkpoint activation (Myung et al. 2003; Ye et al. 2003; Ramey et al. 2004).. This study provides genetic and biochemical evidence that Trf4 and Trf5 make a redundant contribution to genome stability in yeast through control of histone mRNA levels during S phase. We show that the mRNAs coding for the four core histones, but not other cell cycle-regulated transcripts tested, accumulate to abnormally high levels in S phase in a trf4-ts ...
Plant reproduction depends on proper development of the male and the female gametophyte. Due to the reduced size of the angiosperm gametophyte and especially inaccessibility of the female gametophyte, it is challenging to study these fundamental processes. Recent advances in microdissection techniques combined with powerful tools for transcriptome analysis have begun to shed a light on molecular mechanisms underlying the processes. The aim of this thesis was to functionally characterize a maize MATH-BTB (ZmMAB1) protein, which was encoded by a gene highly represented in cDNA libraries of isolated maize egg cells and zygotes. A phylogenetic analysis has shown that ZmMAB1 belongs to an expended group of a previously undescribed maize MATH-BTB gene family with 31 members. RNAi silencing of ZmMAB1 leads to chromosome segregation defects and short spindles during male meiosis. After meiosis-mitosis transition two identical nuclei are formed in mab1 (RNAi) mutants disrupting male and female germline ...
Research conducted in the lab of Associate Professor Jakob Nilsson now provides novel insight into how the cell secures accuracy in this process. Postdoc Gang Zhang investigated how the BubR1 protein functions in the cell, particularly its role at a structure on chromosomes called kinetochores. He found that BubR1 binds to kinetochores in two different ways and that this affects its function. This was a surprising result as previous work had always anticipated only one way that BubR1 binds kinetochores explains Gang Zhang. In collaboration with Blanca Lopez Mendez from the CPR Biophysics facility the molecular basis of the two BubR1 populations was established by combining biophysical measurements and advanced imaging techniques. Using this information it was possible to investigate the function of the two different pools of BubR1 and show that one pool helps establish the connection between kinetochores and microtubules and the other pool controls when the chromosomes should split into the ...
The putative chromatin remodeling enzyme Plk1-interacting checkpoint helicase (PICH) was uncovered as an interaction partner and substrate of the mitotic kinase Plk1. is required for prevention of chromatin bridge formation but not for UFB resolution, and quantitative analyses of UFB and chromatin bridge frequencies suggest that PIK-293 these structures are of different etiologies. We also show that this ATPase activity of PICH is required for temporal and spatial control of PICH localization to chromatin and that Plk1 likely controls PICH localization through phosphorylation of proteins unique from PICH itself. This work strengthens the view that PICH is an important, Plk1-regulated enzyme, whose ATPase activity is essential for maintenance of genome integrity. Although not required for the spindle assembly checkpoint, PICH is clearly important for faithful chromosome segregation. Electronic supplementary material The online version of this article (doi:10.1007/s00412-012-0370-0) contains ...
Essential roles of Drosophila inner centromere protein (INCENP) and aurora B in histone H3 phosphorylation, metaphase chromosome alignment, kinetochore disjunction, and chromosome segregation ...
Monolayers of Xenopus tissue culture cells (XTC) were grown in 66% Leibovitz L-15 media containing 10% fetal calf serum, 1mM sodium pyruvate and antibiotics at ~21°C. Mitotic chromosomes were purified from XTC cells after a 16 hour block in 10µg/ml vinblastine (Sigma-Aldrich). Chromosomes were purified as previously described with minor modifications (Wordeman et al., 1991). Experiments were preformed essentially as described (Mitchison and Kirschner, 1985). Purified mitotic chromosomes were diluted in reactions containing 10 µM tubulin in BRB80 buffer plus 1mM GTP. Reactions were incubated at 37°C for 15 minutes in a water bath and were fixed with 10mM EGS (ethyleneglycol-bis-succinimidyl-succinate) dissolved in BRB80 for 10 minutes at 37°C. Reactions were layered onto a 30% glycerol cushion prepared in BRB80 and chromosome-microtubule complexes were pelleted through the cushion onto poly-l-lysine coated coverlslips. Coverslips were post fixed with ice-cold methanol for 5 minutes at 4°C, ...
Reproductive cells that are destined to become sperm or egg undergo meiotic division during which the chromosome number is halved. As Sluder and McCollum explain in their Perspective, new findings ( Shonn et al.) in yeast show that there is a spindle checkpoint that operates during meiosis to ensure that an equal number of replicated chromosomes arrives at each pole of the cell. One of the components of this meiotic spindle checkpoint turns out to be Mad2, which gives the signal to halt meiosis if it looks like unequal chromosome segregation is taking place. ...
Chromosome instability (CIN) is an inherent enabling characteristic of cancer important for tumor initiation and progression and is observed in a majority of tumors (1⇓-3). It has been proposed that alterations resulting in genome instability happen early during tumor formation, allowing the accumulation of errors during DNA replication, repair, and chromosome segregation, thereby increasing the likelihood that a cell will acquire multiple genetic changes necessary for tumor progression (4). CIN is possibly the major contributor to intratumoral heterogeneity-that is, the presence of genetically distinct populations of cells within a single tumor that impacts treatment strategy, drug resistance, and tumor evolution (5⇓⇓-8). For these reasons, defining genes and pathways that drive CIN and understanding the mechanisms that underlie genome stability will contribute not only to an understanding of tumor etiology and progression but will also be relevant for guiding therapeutic strategies. The ...
Binary fission can refer to cell division in bacteria. Bacteria replicate their chromosomes prior to division, but I dont think that state can be called diploid because the chromosomes are identical. Diploid organisms can be carrying different alleles on each pair of sister chromosomes, but this is not the case for a duplicated bacterial chromosome before cell division. Therefore in my opinion your statement is not necessarily true, at least for bacteria ...
You are cordially invited to the EMBO Workshop on Chromosome Segregation and Aneuploidy, to be held on June 22-26, 2013, on the estate of Nyenrode Castle in Breukelen, The Netherlands ...
Hirano, M., Anderson, D. E., Erickson, H. P., Hirano, T. (2001) Bimodal activation of SMC ATPase by intra- and inter-molecular interactions. Embo Journal, 20 (12). pp. 3238-3250. ISSN 0261-4189 Hirano, T. (2000) Chromosome cohesion, condensation, and separation. Annual Review of Biochemistry, 69. pp. 115-144. ISSN 0066-4154 Hirano, T. (2004) Chromosome shaping by two condensins. Cell Cycle, 3 (1). pp. 26-8. ISSN 1538-4101 (Print) Hirano, T. (2005) Condensins: organizing and segregating the genome. Curr Biol, 15 (7). R265-75. ISSN 0960-9822 (Print) Hirano, T. (2005) SMC proteins and chromosome mechanics: from bacteria to humans. Philos Trans R Soc Lond B Biol Sci, 360 (1455). pp. 507-14. ISSN 0962-8436 (Print) Hirano, T., Kobayashi, R., Hirano, M. (1997) Condensins, chromosome condensation protein complexes containing XCAP-C, XCAP-E and a Xenopus homolog of the Drosophila Barren protein. Cell, 89 (4). pp. 511-21. ISSN 0092-8674 (Print) ...
an animal cell consists of 46 post-mitotic chromosomes in each of its somatic cells. explain how many chromosomes must, Hire Biology Expert, Ask Academics Expert, Assignment Help, Homework Help, Textbooks Solutions
Date: 2019-03-14, Time: 09:00:00, Speaker: Oleg Simakov, Location: GMI Orange Seminar room, Type: Mini-Symposium: Evolutionary Approaches to Chromosome Biology, Institute: University of Vienna, Host: DK Chromosome Dynamics ...
The CRIAW Papers comprises a continuining series of publications: original research papers advancing the knowledge and understanding of womens experience.. Occupational segregation is a fact of life for Canadian women in the labour force in 9181, a fact that has been part of the collective experience of Canadian women as far back as we can analyse. Similar patterns of occupational segregation by gender have been observed in Great Britain and the United States. This pattern of female employmen, however, cannot be assumed to be characteristic of all nations, now even of all industrialized or industrializing nations. While a degree of occupational segregation by gender is observed in most nations, there is considerable cross cultural variation in the pattern. Click here for a FREE copy. ...
Biology portal Here is a list of articles in the Mitosis category of the Biology portal. Mitosis is the process of chromosome segregation and nuclear division that follows replication of the genetic material in eukaryotic cells. This process assures that each daughter nucleus receives a complete copy of the organisms genome. ...
Association, Cancer, Chromosome, Chromosome Segregation, Coding, Cytokinesis, Esophageal Cancer, Kinase, Segregation, Serine, Single Nucleotide Polymorphisms, Threonine, Threonine Kinase
The dynamic composition of proteins associated with nuclear DNA is a fundamental property of chromosome biology. In the chromatin compartment dedicated protein complexes govern the accurate synthesis and repair of the genomic information and define the state of DNA compaction in vital cellular processes such as chromosome segregation or transcription. Unscheduled or faulty association of protein complexes with DNA has detrimental consequences on genome integrity. Consequently, the association of protein complexes with DNA is remarkably dynamic and can respond rapidly to cellular signaling events, which requires tight spatiotemporal control. In this context, the ring-like AAA+ ATPase CDC48/p97 emerges as a key regulator of protein complexes that are marked with ubiquitin or SUMO. Mechanistically, CDC48/p97 functions as a segregase facilitating the extraction of substrate proteins from the chromatin. As such, CDC48/p97 drives molecular reactions either by directed disassembly or rearrangement of ...
n. 1. отделение, выделение, изоляция. segregation of gifted children - выделение ( в особые группы ) одарённых детей. segregation of hardened criminals - изоляция друг от друга /раздельное содержание/ закоренелых преступников. 2..
Catalyzes the exchange of cytoplasmic ADP with mitochondrial ATP across the mitochondrial inner membrane. As part of the mitotic spindle-associated MMXD complex it may play a role in chromosome segregation.
Gaudenz Danuser: Super-Resolution Tracking of Weak Fluorescent Markers in 3D: Application in Dissecting Mechanics of Chromosome Segregation using Fluorescence Imaging and Molecular Genetics in Yeast. 61-64 ...
... and initiates chromosome dimer segregation. The dif site is found at the intersection between the monomers of the chromosome ... FtsK is a 1329 amino acid protein involved in bacterial cell division and chromosome segregation. FtsK stands for "Filament ... Bigot S, Sivanathan V, Possoz C, Barre FX, Cornet F (June 2007). "FtsK, a literate chromosome segregation machine". Molecular ... Pogliano K, Pogliano J, Becker E (December 2003). "Chromosome segregation in Eubacteria". Current Opinion in Microbiology. 6 (6 ...
In late anaphase, chromosomes also reach their overall maximal condensation level, to help chromosome segregation and the re- ... Santaguida S, Amon A (August 2015). "Short- and long-term effects of chromosome mis-segregation and aneuploidy". Nature Reviews ... In this stage, chromosomes are long, thin, and thread-like. Each chromosome has two chromatids. The two chromatids are joined ... Blow JJ, Tanaka TU (November 2005). "The chromosome cycle: coordinating replication and segregation. Second in the cycles ...
Specifically, Draviam monitors chromosome microtubule attachment, end-on conversion, chromosome mis-segregation and how cells ... Dravian, Viji Mythily; Sorger, Peter (2004). "Chromosome segregation and genomic stability". Current Opinion in Genetics & ... progression The ch-TOG/XMAP215 protein is essential for spindle pole organization in human somatic cells Chromosome segregation ... Aneuploidy describes the situation where a cell contains an abnormal number of chromosomes, and often occurs in aggressive ...
"Error-prone chromosome-mediated spindle assembly favors chromosome segregation defects in human oocytes". Science. 348 (6239): ... Mogessie, Binyam; Schuh, Melina (2017). "Actin protects mammalian eggs against chromosome segregation errors". Science. 357 ( ... in which oocytes mature into eggs by extruding half of their chromosomes in a small cell termed the polar body. This requires ... increasing the likelihood of segregation errors. She has also investigated the reasons why the children of older mothers have a ...
Jallepalli PV, Lengauer C (2001). "Chromosome segregation and cancer: cutting through the mystery". Nature Reviews Cancer. 1 (2 ... As previously stated, the disruptions in the chromosome may lead to single chromosome mutations, including deletion, ... a process that ensures that replicated chromosomes are intact before chromosomes are segregated during cell division. In ... This occurs because loss of these genes causes an increase in chromosome fusions, either in an end-to-end manner or through ...
Mary C. Dasso is an American biochemist known for research on chromosome segregation and the discovery of Ran GTPase. She is ... They are now using these systems to examine not only the role of nucleoporins in mitotic chromosome segregation but also how ... Dasso is interested in mechanisms of chromosome segregation. Her group discovered that the Ran GTPase. They showed that Ran ... re-purposed as cells divide to perform transport-independent activities that are essential for accurate chromosome segregation ...
Murray, H; Ferreira, H; Errington, J (Sep 2006). "The bacterial chromosome segregation protein Spo0J spreads along DNA from ... The parABS system is a broadly conserved molecular mechanism for plasmid partitioning and chromosome segregation in bacteria. ... "A spindle-like apparatus guides bacterial chromosome segregation". Nature Cell Biology. 12 (8): 791-8. doi:10.1038/ncb2083. PMC ... Surtees, JA; Funnell, BE (2003). Plasmid and chromosome traffic control: how ParA and ParB drive partition. Current Topics in ...
He generated the first chromosome-wide high resolution maps of proteins involved in chromosome packaging and segregation. He ... "Frank Uhlmann: Mechanism and control of chromosome segregation". The Crick Institute. Archived from the original on 24 May 2015 ... CS1 maint: discouraged parameter (link) Nasmyth, K; Peters, J. M.; Uhlmann, F (2000). "Splitting the chromosome: Cutting the ... "A simple biophysical model emulates budding yeast chromosome condensation". eLife. 4: e05565. doi:10.7554/eLife.05565. PMC ...
... chromosome segregation as well as development and pluripotency. Aberrations in chromatin remodeling proteins are found to be ... DNA repair and chromosome segregation, and therefore exerts tumor-suppressor function. Mutations in such chromatin remodelers ... including chromosome assembly and segregation, DNA replication and repair, embryonic development and pluripotency, and cell- ... Loss of heterozygosity in coding region of p300 (chromosome 22q13) is present in large number of glioblastomas. Further, HATs ...
Chromosome segregation Clastogen Non-disjunction Plante, N. (2003). Molecular toxicology. Taylor & Francis. pp. 63-65. ISBN 978 ... Exposure to fenvalerate raised sex chromosome disomy 1.9-fold and disomy of chromosome 18 by 2.6-fold (Xia et al., 2004). ... and also increased sex chromosome disomy by 1.7-fold and chromosome 18 disomy by 2.2-fold. Humans are exposed to perfluorinated ... An aneugen is a substance that causes a daughter cell to have an abnormal number of chromosomes or aneuploidy. A substance's ...
Chromosome segregation Candida albicans India portal Biology portal Medicine portal "Faculty - JNCASR". www.jncasr.ac.in. 3 ... Essential Components for Chromosome Segregation. Wiley-VCH Verlag GmbH & Co. KGaA. pp. 259-288. doi:10.1002/9783527697274.ch9. ... Sreekumar, Lakshmi; Varshney, Neha; Sanyal, Kaustuv (2017). Chromosome Components Important for Genome Stability in Candida ... "The CENP-A homolog CaCse4p in the pathogenic yeast Candida albicans is a centromere protein essential for chromosome ...
Dworkin J, Losick R (October 2002). "Does RNA polymerase help drive chromosome segregation in bacteria?". Proceedings of the ... SMC proteins responsible for chromosome condensation in eukaryotic cells. Viral DNA packaging motors inject viral genomic DNA ... Peterson CL (November 1994). "The SMC family: novel motor proteins for chromosome condensation?". Cell. 79 (3): 389-92. doi: ...
Seidman, MM; Levine, AJ; Weintraub, H (1979). "The asymmetric segregation of parental nucleosomes during chromosome replication ... Riley, D; Weintraub, H (1979). "Conservative segregation of parental histones during replication in the presence of ...
Falconer, Ester; Lansdorp, Peter M. (August 2013). "Strand-seq: A unifying tool for studies of chromosome segregation". ... Pulse-chase experiments have been used for determining the segregation patterns of chromosomes in addition to studying other ... aneuploid chromosomes and modes of sister chromatid segregation. It can also aid in assembling early-build genomes and ... "The Majority of Multipotent Epidermal Stem Cells Do Not Protect Their Genome by Asymmetrical Chromosome Segregation". Stem ...
Then the metaphase spindle assembles and chromosome segregation can occur. The transcription of Sic1 starts during telophase, ...
For genes on separate chromosomes, each allele pair showed independent segregation. If the first filial generation (F1 ... Gregor Mendel William Bateson Mendelian inheritance Law of dominance Law of segregation Law of independent assortment ... which are also called the Law of Segregation and the Law of Independent Assortment, respectively. ...
His group use budding yeast to study chromosome duplication and segregation. By understanding the processes that occur during ... Moser, Sandra C.; Swedlow, Jason R. (2011). "How to be a mitotic chromosome". Chromosome Research. 19 (3): 307-19. doi:10.1007/ ... The Centre is studying many aspects of the cell cycle, including the way in which chromosomes replicate and separate during ... The driving force behind this process are strands known as microtubules, which pull the chromosomes apart. His work looks at ...
... which generally will produce abnormal chromosome segregation, because in this case, chromosome distribution will not take place ... To ensure that chromosome segregation takes place correctly, cells have developed a precise and complex mechanism. In the first ... both as positive and negative regulators to ensure the proper chromosome segregation in each cell cycle preventing chromosome ... to ensure that chromosome segregation will take place correctly when the cell will divide. Occasionally, one of the two sister ...
Pericentrin has a role in cell division, proper chromosome segregation and cytokinesis. Another gene that has been implicated ...
Shugoshin is a centromere protein for chromosome segregation during meiosis and mitosis. There are two types of Shugoshin ... is responsible for the segregation of chromosomes at centromeres in the M phase. In fission yeast, Sgo2 is localized not only ... which causes new and rapid genetic changes in chromosomes. In Saccharomyces cerevisiae, 15kb region of chromosome 7L in ... Each chromosome has two subtelomeres immediately adjacent to the long (TTAGGG)n repeats. Subtelomeres are considered to be the ...
"Aurora Kinase Promotes Turnover of Kinetochore Microtubules to Reduce Chromosome Segregation Errors". Current Biology. 16 (17 ... "Merotelic kinetochore orientation versus chromosome mono-orientation in the origin of lagging chromosomes in human primary ... The chromosome or chromatid does not properly migrate during anaphase and the daughter cells will lose some genetic information ... In either case, anaphase lag will cause one daughter cell to receive a complete set of chromosomes while the other lacks one ...
"Roles for replichores and macrodomains in segregation of the Escherichia coli chromosome". EMBO Rep. 6 (6): 557-62. doi:10.1038 ... In E. coli chromosomes, the origin and terminus of replication divide the genome into oppositely replicated halves called ... The Escherichia coli chromosome shows two main levels of global organization, macrodomains and replichores. ...
"A stochastic model of kinetochore-microtubule attachment accurately describes fission yeast chromosome segregation". Journal of ... Several chromosomes instantly bioriented, as deduced from the observation that, upon reattachment, the chromosomes moved to the ... Kinetochores link the chromosomes to the mitotic spindle - doing so relies on intricate interactions between microtubules and ... Several methods are postulated by which chromosomes biorient when they are located far from the pole with which they need to ...
Because many cancers may be driven by errors in chromosome segregation, it is hoped that Cheeseman's studies will provide ... a group of proteins required for cell division and chromosome segregation. This core network of proteins facilitates the ... "The human Mis12 complex is required for kinetochore assembly and proper chromosome segregation". J. Cell Biol. 173 (1): 9-17. ... Certain cancer drugs target the connection between chromosomes and spindle microtubules, and some of the major proteins in the ...
"A MatP-divisome interaction coordinates chromosome segregation with cell division in E. coli". The EMBO Journal. 31 (14): 3198- ... and ZapB somehow coordinating interactions between the division machinery and DNA replication during chromosome segregation in ...
Kim, Seul (2020). "PRMT6-mediated H3R2me2a guides Aurora B to chromosome arms for proper chromosome segregation". Nature ... The label-free imaging and quantification of chromosomes were presented. The regulatory pathway of proteasome degradation by ...
Chromosome segregation during meiosis[edit]. Segregation of homologous chromosomes to opposite poles of the cell occurs during ... Proper segregation is essential for producing haploid meiotic products with a normal complement of chromosomes. The formation ... However, in the fission yeast Schizosaccharomyces pombe, when chiasmata are absent, dynein promotes segregation.[22] Dhc1, the ... Dynein is involved in the movement of chromosomes and positioning the mitotic spindles for cell division.[2][3] Dynein carries ...
"Dbl2 Regulates Rad51 and DNA Joint Molecule Metabolism to Ensure Proper Meiotic Chromosome Segregation". PLoS Genetics. 12 (6 ... "Entrez Gene: Chromosome 4 open reading frame 21". Brannvoll A, Xue X, Kwon Y, Kompocholi S, Simonsen AK, Viswalingam KS, et al ... ZGRF1 is located on the fourth chromosome on the 4q25 position near the LARP7 gene. It is encoded for on the minus strand. ... DUF domains are involved in telomere maintenance and meiotic segregation. AAA_11 and AAA_12 contain a P-loop motif which are ...
At ETH Zürich Bomblies studies the evolution of meiosis, particularly recombination and chromosome segregation. In her spare ...
Wurzenberger C, Held M, Lampson MA, Poser I, Hyman AA, Gerlich DW (2012). "Sds22 and Repo-Man stabilize chromosome segregation ...
... and not sex segregation".[1]:229 [2][7][8] "Segregation" is a term that has long been associated with racial segregation in the ... chromosomes and anatomy' at birth.[32] ... Sex-separation in public toilets (also called sex segregation ... Some scholars have tied toilet sex-separation to segregation based on race discrimination in the US.[67] Advocates of this view ... Ancient evidence, including art-work, confirms widespread use of sex-separation (or sex segregation), especially in multi-use ...
... separate sexes and sex chromosomes, segregation distortion and repetitive DNA. ...
... in males with normal chromosomes because they have only one X chromosome and few of the same genes are on the Y chromosome. ... Gupta, R.S.; Chan, D.H.Y.; Siminovitch, L. (1978). "Evidence obtained by segregation analysis for functional hemizygosity at ... A chromosome in a diploid organism is hemizygous when only one copy is present.[2] The cell or organism is called a hemizygote ... Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each ...
Deletion in the 22q11.2 region of chromosome 22 has been associated with schizophrenia and autism.[22][23] Schizophrenia and ... The disease is caused by a defect in a single gene on chromosome 12 that codes for enzyme phenylalanine hydroxylase , that ... and can be caused by any of a large number of mutations in the single gene on chromosome 12 that codes for the enzyme ... especially if the gene is located on an autosomal chromosome.[14] ...
condensed chromosome. • nuclear chromosome, telomeric region. • nucleus. • nuclear chromatin. • lateral element. • cytosol. • ... Crickard JB, Kaniecki K, Kwon Y, Sung P, Greene EC (2018). "Spontaneous self-segregation of Rad51 and Dmc1 DNA recombinases ... nuclear chromosome. • mitochondrial matrix. • nucleolus. • mitochondrion. • perinuclear region of cytoplasm. • chromatin. • ... condensed nuclear chromosome. • macromolecular complex. Biological process. • regulation of protein phosphorylation. • strand ...
選擇可以作用在基因而非個體的層級,即使降低個體的適應度,自私DNA仍然可以演化,造成基因組內部衝突。例子包括跳躍子、減數分裂驅動者(meiotic drivers)、殺手X染色體(killer X chromosomes)、自私粒線體(selfish ... segregation load)[9]。 ... Thomas Jr, C. A. The genetic organization of chromosomes (PDF) ... Crosland, M.W.J., Crozier, R.H. Myrmecia pilosula, an ant with only one pair of chromosomes. Science. 1986, 231 (4743):
... called 46/47 XY/XXY mosaic wherein some of the patient's cells contain XY chromosomes, and some contain XXY chromosomes. The 46 ... "Somatic crossing-over and segregation in Drosophila melanogaster". Genetics 21, 625-730. ... where a fly possessing two X chromosomes is a female and a fly possessing a single X chromosome is a sterile male, a loss of an ... This may be caused by a nondisjunction event in an early mitosis, resulting in a loss of a chromosome from some trisomic cells. ...
"Variation in crossover frequencies perturb crossover assurance without affecting meiotic chromosome segregation in ... "MutS homolog 4 localization to meiotic chromosomes is required for chromosome pairing during meiosis in male and female mice". ... "hMSH4-hMSH5 recognizes Holliday Junctions and forms a meiosis-specific sliding clamp that embraces homologous chromosomes". ...
"A Y Chromosome Census of the British Isles" (PDF).. *^ Härke, Heinrich; Thomas, Mark G; Stumpf, Michael P H. "Integration ... In 1253 the Statute of Jewry, reinforced physical segregation and demanded a previously notional requirement to wear square ... "Y Chromosome Evidence for Anglo-Saxon Mass Migration".. *^ " ...
The physical basis of the independent assortment of chromosomes is the random orientation of each bivalent chromosome along the ... Law of Segregation of genes (the "First Law")[edit]. Figure 1 Dominant and recessive phenotypes.. (1) Parental generation.. (2 ... In independent assortment, the chromosomes that result are randomly sorted from all possible maternal and paternal chromosomes ... The zygote will normally end up with 23 chromosomes pairs, but the origin of any particular chromosome will be randomly ...
In Gammaproteobacteria, adenine methylation provides signals for DNA replication, chromosome segregation, mismatch repair, ... Methylation of cytosines can also persist from the germ line of one of the parents into the zygote, marking the chromosome as ... In 2008, a consensus definition of the epigenetic trait, "stably heritable phenotype resulting from changes in a chromosome ... Specific epigenetic processes include paramutation, bookmarking, imprinting, gene silencing, X chromosome inactivation, ...
His story lines have focused on the segregation of those with disabilities in the UK in the 1950s, and also romantic ... "A gene for ataxic cerebral palsy maps to chromosome 9p12-q12". European Journal of Human Genetics. 8 (4): 267-272. doi:10.1038/ ...
Male birds have two Z chromosomes (ZZ), and female birds have a W chromosome and a Z chromosome (WZ).[62] ... "Variation in Altitudinal Migration, Winter Segregation, and Site Tenacity in two subspecies of Dark-eyed Juncos in the ... Chromosomes. Birds have two sexes: either female or male. The sex of birds is determined by the Z and W sex chromosomes, rather ... than by the X and Y chromosomes present in mammals. ...
During meiosis, chromosomes assort randomly into gametes, such that the segregation of alleles of one gene is independent of ... when two genes are located on different chromosomes or when they are widely separated on the same chromosome. This is a ... Markers on different chromosomes are perfectly unlinked. Genetic linkage is the most prominent exception to Gregor Mendel's Law ... Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the ...
... s have 21 pairs of chromosomes (2n=42).[106] The genome of live whales can be examined by recovering shed skin.[107] ... The main driving force for the sexual segregation of adult sperm whales is scramble competition for mesopelagic squid.[168] ...
In evolution, this chromosome has lost most of its content and also most of its genes, while the X chromosome is similar to the ... These observations of discrete inheritance and the segregation of alleles are collectively known as Mendel's first law or the ... During crossover, chromosomes exchange stretches of DNA, effectively shuffling the gene alleles between the chromosomes.[59] ... Chromosomes are copied, condensed, and organized. Then, as the cell divides, chromosome copies separate into the daughter cells ...
Jackson, John P. (2005). Science for Segregation: Race, Law, and the Case against Brown v. Board of Education. NYU Press. ISBN ... When looking at the Y-chromosome there are three large haplogroups which account for most of Europe's patrilineal descent.[120] ... November 2000), "The genetic legacy of Paleolithic Homo sapiens sapiens in extant Europeans: a Y chromosome perspective", ...
This incorrect segregation of chromosomes may result from hypomethylation of repeat sequences present in pericentromeric DNA, ... Sex chromosomes contribute to the majority of chromosome loss events with increasing age. In females, the X chromosome can ... Micronucleus is the name given to the small nucleus that forms whenever a chromosome or a fragment of a chromosome is not ... Micronuclei originating from chromosome loss events and acentric chromosome fragments can be distinguished using pancentromeric ...
In gene conversion, a section of genetic material is copied from one chromosome to another, without the donating chromosome ... Achiasmatic chromosomal segregation is well documented in male Drosophila melanogaster. Heterochiasmy occurs when recombination ... This process appears to be an adaptation for repairing DNA damages in the recipient chromosome by HRR.[11] Transformation may ... Indicated on the right side is a "crossover" (CO) type, where the flanking regions of the chromosomes are exchanged, and on the ...
... not considering that crossover events can take place at most points along each chromosome. The X and Y chromosomes undergo no ... Meiosis results in a random segregation of the genes that each parent contributes. Each parent organism is usually identical ... In humans, (2²²)² = 17.6x1012 chromosomally different zygotes are possible for the non-sex chromosomes, even assuming no ... haploid number of chromosomes)[12] - a growing pollen tube therefore contains three separate nuclei, two sperm and one tube.[13 ...
chromosome segregation. • protein K6-linked ubiquitination. • intrinsic apoptotic signaling pathway in response to DNA damage. ... condensed chromosome. • cytoplasm. • chromosome. • cell nucleus. • lateral element. • macromolecular complex. • ... condensed nuclear chromosome. • gamma-tubulin ring complex. • BRCA1-A complex. • ubiquitin ligase complex. • plasma membrane. • ... a b US patent 5837492, Tavtigian SV, Kamb A, Simard J, Couch F, Rommens JM, Weber BL, "Chromosome 13-linked breast cancer ...
... segregation of ice occurs in intercellular spaces.[62] This may or may not be lethal, depending on the hardiness of the tissue ... and examination of chromosomes in maize allowed Barbara McClintock to demonstrate their connection to inherited traits.[102] ...
Crossing over is essential for the normal segregation of chromosomes during meiosis.[citation needed] Crossing over also ... So, when the chromosomes go on to meiosis II and separate, some of the daughter cells receive daughter chromosomes with ... this mutant gave rise to spore viability patterns suggesting that segregation of non-exchange chromosomes occurred efficiently ... "Variation in crossover frequencies perturb crossover assurance without affecting meiotic chromosome segregation in ...
... chromosome segregation, and cytokinesis. Eukaryotic cell division either involves mitosis or a more complex process called ... There are two distinct sex chromosomes, the X chromosome and the Y chromosome. A diploid human cell has 23 chromosomes from ... In each double chromosome there are two copies of that chromosome's DNA molecule. During mitosis the double chromosomes are ... Information from the chromosome 2 DNA gained from one parent (red) will transfer over to the chromosome 2 DNA molecule that was ...
The final chromosomes in the two human gametes are called sex chromosomes because of their role in sex determination. Ova ... sex segregation, gender equality, marriage, abortion, homosexuality) ... About half of spermatozoa also have this same X chromosome, the rest have a Y-chromosome. At fertilization the gametes fuse to ... In fact, there are typically many of these "books", called chromosomes. Human gametes usually have 23 chromosomes, 22 of which ...
Vegetative segregation[edit]. Vegetative segregation, the random partitioning of cytoplasm, is a distinguishable characteristic ... because plastid genes are usually on a single chromosome and recombination is limited by uniparental inheritance.[4] ... It refers to the selective segregation of certain genotypes in mitochondrial DNA that allows the favoured genotype to thrive. ... Although a single mutational event might be rare in its generation, repeated mitotic segregation and clonal expansion can ...
Ploidy/Chromosomes in human. DNA copy number/Chromatids in human. Process entered by cell. Duration ... also known as distance segregation). These unique traits allow researchers to study the force created by the spindle poles to ... allow the chromosomes to move, cleavage furrow management and distance segregation.[19][20] ... Mutations in leptotene spermatocytes can result in premature chromosome condensation.[13]. Mutations in Mtap2, a microtubule- ...
After the first chromosome segregation in meiosis I is complete, there is further chromosome segregation during the second ... Both proper initial segregation of chromosomes in prophase I and the next chromosome segregation during equational division in ... Chromosome segregation also occurs in prokaryotes. However, in contrast to eukaryotic chromosome segregation, replication and ... Improper chromosome segregation can result in aneuploid gametes having either too few or too many chromosomes. The second stage ...
CSE1L chromosome segregation 1 like [Homo sapiens] CSE1L chromosome segregation 1 like [Homo sapiens]. Gene ID:1434 ... CSE1 chromosome segregation 1-like. cellular apoptosis susceptibility protein. chromosome segregation 1-like protein. ... chromosome segregation 1 likeprovided by HGNC. Primary source. HGNC:HGNC:2431 See related. Ensembl:ENSG00000124207 MIM:601342 ... CSE1L chromosome segregation 1 like [ Homo sapiens (human) ] Gene ID: 1434, updated on 3-May-2020 ...
The Saccharomyces Genome Database (SGD) provides comprehensive integrated biological information for the budding yeast Saccharomyces cerevisiae.
In most animal species, chromosome segregation during female meiosis occurs on spindles assembled in the absence of the major ... Acentrosomal spindle assembly and chromosome segregation during oocyte meiosis.. Dumont J1, Desai A. ... During anaphase I, dissolution of chromosome arm cohesion leads to reductional segregation of homologs. Sister chromatids are ... The nature of the link between microtubules and chromosomes, and whether microtubule assembly and/or sliding promote chromosome ...
Knockdown of Gie in Drosophila cells also blocked normal sister chromosome segregation but did not block the progression of ... Named Gie1 and Gie2 (GTPases indispensible for equal segregation of chromosomes), the new members share about 30% amino acid ... Novel small GTPase subfamily capable of associating with tubulin is required for chromosome segregation. J. Cell Sci. 117, 4705 ... may localize to the spindle mid-zone and mid-body to control chromosome segregation. ...
Abnormal segregation can cause cell death or diseases like Down syndrome and cancer. Filamentous spindle fibers must bind to ... For the spindle fiber to be correctly joined, the chromosome must have heterochromatin. However, the mechanism for forming this ... chromosomes need to be evenly segregated. This equal distribution is important to accurately pass genetic information to the ... The chromosome centromere is an essential area for chromosome movement and accurate segregation in which a kinetochore ...
Home Blog Entry New insight into chromosome segregation: Centromere-independent kinetochore assembly ... New insight into chromosome segregation: Centromere-independent kinetochore assembly. April 28, 2011. ... provides fascinating new insight into the complex of proteins that orchestrates the proper segregation of human chromosomes ... Duplicated chromosomes are attached together at a region called the centromere. The centromere plays an important role in the ...
Chromosome Segregation; Centrosomes and Centrioles; Ploidy, Chromosome Segregation Errors, and Disease; Asymmetric Cell ... Organizing Chromosomes during Segregation. Noncanonical Biogenesis of Centrioles and Basal Bodies. Catarina Nabais, Sónia Gomes ... Impact of Centrosome Aberrations on Chromosome Segregation and Tissue Architecture in Cancer. Erich A. Nigg, Dominik Schnerch, ... The 82nd Cold Spring Harbor Symposium focused on Chromosome Segregation & Structure and addressed the enormous progress in our ...
Efficient chromosome segregation requires the co-ordination of several cellular processes; some of which involve gross ... Chromosome segregation is an essential feature of the eukaryotic cell cycle. ... Chromosome segregation is an essential feature of the eukaryotic cell cycle. Efficient chromosome segregation requires the co- ... The role of SUMO in chromosome segregation Chromosoma. 2007 Feb;116(1):15-20. doi: 10.1007/s00412-006-0079-z. Epub 2006 Oct 10 ...
... the link between chromosome and kinetochore would fail, as would chromosome segregation and cell division. ... Whitehead Institute researchers have determined the organization of a protein complex that is critical during chromosome ... segregation. Without the solid foundation supplied by this complex, which is called the Constitutive Centromere-Associated ... as would chromosome segregation and cell division. "The CCAN forms the critical connection between the DNA and the segregation ...
Genetic Analysis of Hybrid Cells Using Isozyme Markers as Monitors of Chromosome Segregation. ... and adenylate kinase are syntenic on mouse chromosome 4 and human chromosome 1p, Proc. Natl. Acad. Sci. USA 75:2382-2386.PubMed ... Genetic Analysis of Hybrid Cells Using Isozyme Markers as Monitors of Chromosome Segregation. In: Shay J.W. (eds) Techniques in ... McKusick, V. A., and Ruddle, F. H., 1977, The status of the gene map of human chromosomes, Science 196:390-405.PubMedCrossRef ...
Chromosome segregation and cell division are essential, highly ordered processes that depend on numerous protein complexes. ... Chromosome segregation and cell division are essential, highly ordered processes that depend on numerous protein complexes. ... Systematic analysis of human protein complexes identifies chromosome segregation proteins Science. 2010 Apr 30;328(5978):593-9. ... large complexes that are essential for spindle assembly and chromosome segregation. The approaches we describe here are ...
Our results are consistent with a role for ObgE in chromosome partitioning, with defects in chromosome segregation observed ... A reasonable hypothesis is that ObgE is required to license chromosome segregation and, in its absence, chromosomes are ... The mechanism of bacterial chromosome segregation is still mysterious, although the demonstration of segregation defects ... loss of sister cohesion triggers global chromosome movement and mediates chromosome segregation. Cell 121: 899-911. *CrossRef ...
How do these chromosome segregation defects account for the observed patterns of NPC aneuploidy? Lagging chromosomes and ... B-E, Chromosome segregation defects and consequently aneuploidy can result from lagging chromosomes (B), supernumerary ... Chromosome segregation defects can lead to aneuploidy. A, During normal mitosis, metaphase chromosomes establish bipolar ... The euploid chromosome number for Mus musculus is 40. The chromosome spread has only one copy of chromosomes 3 and 10 (38, XY ...
In the majority of bacterial species, faithful chromosome segregation is… ... Proper chromosome segregation during cell division is essential in all domains of life. ... Proper chromosome segregation during cell division is essential in all domains of life. In the majority of bacterial species, ... Additionally, we discuss outstanding questions and challenges in understanding bacterial chromosome segregation. ...
RED1: a yeast gene required for the segregation of chromosomes during the reductional division of meiosis. B Rockmill and G S ... RED1: a yeast gene required for the segregation of chromosomes during the reductional division of meiosis ... Expression and DNA sequence of RED1, a gene required for meiosis I chromosome segregation in yeast ... RED1: a yeast gene required for the segregation of chromosomes during the reductional division of meiosis ...
However, when crossed to the wild type, hybrid progeny suffered from extensive mis-segregation. Genotypes include simple ... aneuploids, novel genetic rearrangements, and in extreme cases haploids where all the chromosomes from one parent are lost. ...
Genetic assays of meiotic chromosome segregation. To test whether dtopors mutations caused sex chromosome and fourth chromosome ... Nuclear Structure and Chromosome Segregation in Drosophila Male Meiosis Depend on the Ubiquitin Ligase dTopors. Maiko Matsui, ... At anaphase/telophase I, chromosome segregation appeared normal in dtopors f05115/+; mnmZ5578/+ (n = 30). In dtopors f05115/+; ... Nuclear Structure and Chromosome Segregation in Drosophila Male Meiosis Depend on the Ubiquitin Ligase dTopors. Maiko Matsui, ...
Double or nothing: a Drosophila mutation affecting meiotic chromosome segregation in both females and males.. D P Moore, W Y ... Double or nothing: a Drosophila mutation affecting meiotic chromosome segregation in both females and males.. D P Moore, W Y ... Double or nothing: a Drosophila mutation affecting meiotic chromosome segregation in both females and males.. D P Moore, W Y ... Dub is unusual in that it causes aberrant chromosome segregation almost exclusively in meiosis I in both sexes. In Dub mutant ...
However, only a few studies have examined the relationship between chromosome segregation errors during early cleavage and ... These results suggest that early chromosome segregation error causing micronuclei formation affects ploidy and development to ... aneuploidy resulting from chromosome segregation error is considered responsible for pregnancy loss. ... We showed that some embryos exhibiting early chromosomal segregation error and formation of micronuclei retained their ...
Hence, the segregation of the genome is coordinated in time and space.. To study chromosome segregation we implement a multi- ... generating offspring with a correct number of chromosomes. Errors made during chromosome segregation e.g., due to a lack or ... As chromosome segregation and the proteins involved are evolutionary conserved we study them in the yeast Saccharomyces ... To identify new proteins involved in chromosome segregation we perform protein affinity purifications and yeast two-hybrid ...
This protocol describes an easy and convenient method to label and visualize live chromosomes in mitotic cells using Histone2B- ... Cell cycle control checkpoints that ensure accurate chromosome segregation prevent aneuploidy and cell transformation 1,2,3. In ... Live Cell Imaging of Chromosome Segregation During Mitosis. Prajakta Varadkar1, Kazuyo Takeda2, Brenton McCright1 ... Varadkar, P., Takeda, K., McCright, B. Live Cell Imaging of Chromosome Segregation During Mitosis. J. Vis. Exp. (133), e57389, ...
Laboratory for Chromosome Segregation Website , RIKEN Center for Biosystems Dynamics Research. You are encouraged to contact to ... The Laboratory for Chromosome Segregation is seeking to recruit a motivated research scientist who carries out researches ... Laboratory for Chromosome Segregation. RIKEN Center for Biosystems Dynamics Research. (Team Leader: Tomoya Kitajima) ... For more information about researches in the Laboratory for Chromosome Segregation, please refer to the following website:. ...
Cortical CDC42 depends on polarization directed by chromosomes, which are positioned near the cortex to allow the asymmetric ... from the cell cortex regulated microtubule tyrosination to induce spindle asymmetry and that non-Mendelian segregation depended ...
... as more is known about the basic mechanisms of cell cycle regulation and chromosome segregation, certain lagging chromosome ... Mitotic Centromere-associated Kinesin Is Important for Anaphase Chromosome Segregation. Todd Maney, Andrew W. Hunter, Mike ... Effect of endogenous MCAK depletion on chromosome segregation. Mitotic cells triple-labeled with anti-MCAK (A, D, G, J, M); ... 1994) Video time-lapse study of mitosis in binucleate V79 cells: chromosome segregation and cleavage. Mutagenesis 9:117-123, ...
Cdk5rap2 regulates centrosome function and chromosome segregation in neuronal progenitors Message Subject (Your Name) has sent ... Cdk5rap2 regulates centrosome function and chromosome segregation in neuronal progenitors. Sofia B. Lizarraga, Steven P. ... Cdk5rap2 regulates centrosome function and chromosome segregation in neuronal progenitors. Sofia B. Lizarraga, Steven P. ... Cdk5rap2 regulates centrosome function and chromosome segregation in neuronal progenitors. Sofia B. Lizarraga, Steven P. ...
Accurate chromosome segregation depends on the kinetochore, the complex of proteins that link microtubules to centromeric DNA1 ... Recruiting a microtubule-binding complex to DNA directs chromosome segregation in budding yeast. Nature Cell Biology 11(9): ... Recruiting a Microtubule-Binding Complex to DNA Directs Chromosome Segregation in Budding Yeast. ... a single kinetochore protein to DNA triggers the assembly of the complex structure that directs mitotic chromosome segregation. ...
2011). Chromosome segregation errors as a cause of DNA damage and structural chromosome aberrations. Science 333, 1895-1898. ... 2015). Short- and long-term effects of chromosome mis-segregation and aneuploidy. Nat. Rev. Mol. Cell Biol. 16, 576-576. doi: ... Chromosomes trapped in micronuclei are liable to segregation errors Message Subject (Your Name) has sent you a message from ... Chromosomes trapped in micronuclei are liable to segregation errors. Mar Soto, Iraia García-Santisteban, Lenno Krenning, René H ...
... that the environment surrounding a cell plays an integral role in its ability to accurately segregate its chromosomes. ... known as chromosome mis-segregation. Some errors simply result in damage to the DNA. Other errors can result in the chromosomes ... "Chromosome segregation has been studied in a dish for decades," Knouse says. "I think the assumption was … a cell would ... But once they were placed into a dish, the frequency of chromosome mis-segregation drastically increased. The cells that were ...
Preferential chromosome segregation is predicted to depend on spindle asymmetry. We show that meiosis I (MI) spindles are ... Fixation of Rb fusions can be explained by meiotic drive: biased chromosome segregation during female meiosis. However, there ... We exploit Rb fusions to study mechanisms of meiotic chromosome segregation when erroneous kinetochore-MT attachments are ... We propose that chromosome position on the spindle provides spatial cues for the fidelity of meiotic cell division. ...
  • This segregation process occurs during both mitosis and meiosis. (wikipedia.org)
  • Chromosome segregation occurs at two separate stages during meiosis called anaphase I and anaphase II (see meiosis diagram). (wikipedia.org)
  • During the phase of meiosis labeled "interphase s" in the meiosis diagram there is a round of DNA replication, so that each of the chromosomes initially present is now composed of two copies called chromatids. (wikipedia.org)
  • These chromosomes (paired chromatids) then pair with the homologous chromosome (also paired chromatids) present in the same nucleus (see prophase I in the meiosis diagram). (wikipedia.org)
  • Following recombination, chromosome segregation occurs as indicated by the stages metaphase I and anaphase I in the meiosis diagram. (wikipedia.org)
  • The second stage at which segregation occurs during meiosis is prophase II (see meiosis diagram). (wikipedia.org)
  • Thus the two chromatids comprising each chromosome separate into different nuclei, so that each nucleus gets a single set of chromatids (now called chromosomes) and each nucleus becomes included in a haploid gamete (see stages following prophase II in the meiosis diagram). (wikipedia.org)
  • After the first chromosome segregation in meiosis I is complete, there is further chromosome segregation during the second equational division of meiosis II. (wikipedia.org)
  • Both proper initial segregation of chromosomes in prophase I and the next chromosome segregation during equational division in meiosis II are required to generate gametes with the correct number of chromosomes. (wikipedia.org)
  • Acentrosomal spindle assembly and chromosome segregation during oocyte meiosis. (nih.gov)
  • In most animal species, chromosome segregation during female meiosis occurs on spindles assembled in the absence of the major microtubule-organizing center, the centrosome. (nih.gov)
  • Here, we review recent work on acentrosomal spindle formation and chromosome alignment/separation during oocyte meiosis in different animal models. (nih.gov)
  • Dub is unusual in that it causes aberrant chromosome segregation almost exclusively in meiosis I in both sexes. (genetics.org)
  • Dub results in nondisjunction of all chromosomes in meiosis I of males, although the levels are lower than in females. (genetics.org)
  • Fixation of Rb fusions can be explained by meiotic drive: biased chromosome segregation during female meiosis. (upenn.edu)
  • In meiosis I, homologous chromosomes segregate, while sister chromatids remain together. (elifesciences.org)
  • Here we show that preventing microtubule-kinetochore interactions during premeiotic S phase and prophase I is essential for establishing the meiosis I chromosome segregation pattern. (elifesciences.org)
  • Premature interactions of kinetochores with microtubules transform meiosis I into a mitosis-like division by disrupting two key meiosis I events: coorientation of sister kinetochores and protection of centromeric cohesin removal from chromosomes. (elifesciences.org)
  • We propose that inhibition of microtubule-kinetochore interactions during premeiotic S phase and prophase I is central to establishing the unique meiosis I chromosome segregation pattern. (elifesciences.org)
  • During meiosis I, homologous chromosomes are separated. (elifesciences.org)
  • Subsequently, during meiosis II, the sister chromatids separate to produce a total of four products, each with half the number of chromosomes as the original cell. (elifesciences.org)
  • During meiosis I, on the other hand, they attach to kinetochores in a manner so the homologous chromosomes are pulled apart. (elifesciences.org)
  • These results demonstrate that preventing premature microtubule-kinetochore interactions is essential for establishing a meiosis I-specific chromosome architecture, and they also provide fresh insights into how the molecular machinery that is responsible for mitotic chromosome segregation can be modulated to achieve meiosis. (elifesciences.org)
  • In the course of maturation, they divide their set of chromosomes in half via a specialized cell division termed meiosis. (mpg.de)
  • Actin protects mammalian oocytes from defects during chromosome segregation," points out Melina Schuh, Director of the Department of Meiosis at the institute. (mpg.de)
  • We observed a dramatic loss of spore viability in fission yeast lacking all four TLSPs, which is accompanied by disruptions in chromosome segregation during meiosis I and II. (caltech.edu)
  • During meiosis, diploid organisms reduce their chromosome number by half to generate haploid gametes. (prolekare.cz)
  • However, these anaphase I bridges were often able to resolve in a LEM-3 nuclease dependent manner, and chromosome tethers that persisted were frequently resolved during Meiosis II by a second mechanism that preferentially segregates the tethered sister chromatid into the polar body. (prolekare.cz)
  • Altogether these findings demonstrate that excess interfering crossovers can severely impact chromosome patterning and segregation, highlighting the importance of limiting the number of recombination events between homologous chromosomes for the proper execution of meiosis. (prolekare.cz)
  • 10. Kaitna S, Pasierbek P, Jantsch M, Loidl J, Glotzer M. The aurora B kinase AIR-2 regulates kinetochores during mitosis and is required for separation of homologous chromosomes during meiosis. (prolekare.cz)
  • Homologous recombination is essential for crossover (CO) formation and accurate chromosome segregation during meiosis. (bionity.com)
  • Cohesin complexes maintain sister chromatid cohesion to ensure proper chromosome segregation during mitosis and meiosis. (plantcell.org)
  • Chromosomes and genes share all of the following characteristics except that Possible Answers A. they both undergo segregation during meiosis. (coursehero.com)
  • A. they both undergo segregation during meiosis. (coursehero.com)
  • A novel chromosome segregation mechanism during female meiosis. (escholarship.org)
  • Accurate chromosome segregation during meiosis depends on protein linkages (cohesion) that hold sister chromatids together. (prolekare.cz)
  • Because the majority of human oocytes remain arrested for decades, the continued physical association of recombinant homologs and their accurate segregation during meiosis I demands that cohesion along the arms of sister chromatids remain intact during this extended timeframe. (prolekare.cz)
  • Chromosome segregation errors during female meiosis are the leading cause of miscarriages and birth defects in humans [8] . (prolekare.cz)
  • https://doi.org/10.1083/jcb.202005179 ) show that kinetochore proteins KNL-1 and KNL-3 are required for early stages of anaphase during female meiosis, suggesting a new kinetochore-based model of chromosome segregation. (rupress.org)
  • Meiosis consists of two consecutive chromosome segregation events preceded by a single round of DNA replication. (rupress.org)
  • Homologous chromosomes are separated in meiosis I, which is followed by sister chromatid separation in meiosis II to produce haploid gametes. (rupress.org)
  • In many organisms, including mammals, oocytes lack centrosomes, and it has been of great interest to clarify the mechanisms used to ensure chromosomes are properly segregated during female meiosis ( 5 , 6 ). (rupress.org)
  • The spindle assembly checkpoint (SAC) monitors attachment to microtubules and tension on chromosomes in mitosis and meiosis. (uni-bielefeld.de)
  • Human female meiosis revised: new insights into the mechanisms of chromosome segregation and aneuploidies from advanced genomics and time-lapse imaging. (scienceopen.com)
  • Rescue of a single yeast artificial chromosome from a cotransformation event utilizing segregation at meiosis. (ox.ac.uk)
  • We present a simple method to rescue the required YAC that utilizes the segregation of chromosomes at meiosis. (ox.ac.uk)
  • In both meiosis and mitosis, accurate chromosome segregation relies on the correct orientation of sister chromatids during metaphase, which ensures bipolar spindle attachment. (ed.ac.uk)
  • In biology , meiosis is the process by which the number of chromosomes in a cell nucleus is halved during the formation of germ cells ( eggs and sperm ). (newworldencyclopedia.org)
  • In meiosis, the diploid cell's genome, which is composed of ordered structures of coiled DNA called chromosomes, is replicated once and separated twice, producing four haploid cells, with each containing half (one set) of the original cell's chromosomes. (newworldencyclopedia.org)
  • Meiosis uses many biochemical processes that are similar to those used in mitosis in order to distribute chromosomes among the resulting cells, but the outcome is very different. (newworldencyclopedia.org)
  • The significance of meiosis for reproduction and inheritance , however, was not described until 1890 by German biologist August Weismann (1834-1914), who noted that two cell divisions were necessary to transform one diploid cell into four haploid cells if the number of chromosomes had to be maintained. (newworldencyclopedia.org)
  • In 1911, American geneticist Thomas Hunt Morgan (1866-1945) observed crossover (an exchange of material between two chromosomes) in Drosophila melanogaster meiosis and provided the first true genetic interpretation of meiosis. (newworldencyclopedia.org)
  • Chromosome segregation during meiosis is a complex process, which leads to production of four haploid gametes from two precursor cells. (edu.pl)
  • To study the role of Prp4 in meiosis, we analysed chromosome segregation in a strain carrying conditional analog-sensitive allele of Prp4 protein kinase (prp4-as2). (edu.pl)
  • Our data show, that Prp4 protein kinase plays important role in chromosome segregation during meiosis, as revealed by enhanced missegregation of chromosomes in prp4-as2 mutant cells. (edu.pl)
  • Rabitsch KP, Gregan J, Schleiffer A, Javerzat JP, Eisenhaber F, Nasmyth K (2004) Two fission yeast homologs of Drosophila Mei-S332 are required for chromosome segregation during meiosis I and II. (edu.pl)
  • Heterochromatin assembly at the centromeres facilitates both kinetochore formation and sister chromatid cohesion, and the formation of specialized chromatin structures at telomeres serves to maintain the length of telomeric repeats, to suppress recombination, and to aid in formation of a bouquet-like structure that facilitates homologous chromosome pairing during meiosis. (pnas.org)
  • In this study, we examine the effects of deletions of the fission yeast RNAi machinery on chromosome dynamics during mitosis and meiosis. (pnas.org)
  • This study demonstrates that the fission yeast RNAi machinery is required for the proper regulation of chromosome architecture during mitosis and meiosis. (pnas.org)
  • Haploid gametes are produced in meiosis, a special form of cell division where DNA replication is followed by two rounds of chromosome segregation and gametogenesis. (mpg.de)
  • Homologous chromosomes segregate in meiosis I, whereas chromatids disjoin in meiosis II. (mpg.de)
  • Scientists of the research group Chromosome Biology now revealed how the conserved Hrr25 kinase of yeast coordinates production and packaging into gametes of the single-copy genome in meiosis II. (mpg.de)
  • Regulation of chromosome segregation by ORD and dRING during Drosophila meiosis. (dartmouth.edu)
  • During mid-late G2 of meiosis , we observe that ORD localizes to the chromosome arms where it extensively colocalizes with dRING . (dartmouth.edu)
  • These results are consistent with the model that interaction of ORD and dRING facilitates proper segregation of chromosomes during Drosophila meiosis . (dartmouth.edu)
  • End-on contact with a kinetochore results in `capture' of a chromosome and stabilization of the microtubule to form a kinetochore fiber (orange). (nih.gov)
  • Kinetochore fibers are periodically destabilized and re-established to maintain oscillating chromosomes at the spindle equator during the extended prometaphase. (nih.gov)
  • The chromosome centromere is an essential area for chromosome movement and accurate segregation in which a kinetochore structure forms a connection to a spindle fiber. (eurekalert.org)
  • The formation of that heterochromatin structure is known to be essential for the kinetochore formation on the chromosome centromere. (eurekalert.org)
  • The kinetochore is composed of more than one hundred proteins and serves as the binding site for microtubules that are attached to opposite ends of the cell and will physically pull the two identical chromosomes apart. (scienceblog.com)
  • Without a centromere and a kinetochore, a chromosome would be lost during cell division. (scienceblog.com)
  • We found that although CENP-A is essential for specifying the site of kinetochore formation, CENP-T and CENP-C can act as key components to drive assembly of a functional kinetochore capable of binding microtubules to allow accurate chromosome segregation," concludes first author Dr. Karen Gascoigne. (scienceblog.com)
  • During chromosome segregation, the kinetochore serves as an attachment point for microtubules, which exert strong forces as they winch the chromosomes apart. (eurekalert.org)
  • In human cells, a protein complex termed the Constitutive Centromere-Associated Network (CCAN), is critical for recruiting the kinetochore to a specific point on each chromosome. (eurekalert.org)
  • Without the solid foundation provided by the 16-subunit CCAN, the link between chromosome and kinetochore would fail, as would chromosome segregation and cell division. (eurekalert.org)
  • Learning about its organization can tell us how it targets specifically to the right part of the chromosome - the centromere - and the properties that underlie its role in kinetochore stability. (eurekalert.org)
  • The histone protein CENP-A is the epigenetic mark for centromeres, but CENP-A nucleosomes can be sparsely integrated throughout the chromosome without recruiting a kinetochore. (eurekalert.org)
  • Errors made during chromosome segregation e.g., due to a lack or overexpression of a single kinetochore protein, can lead to daughter cells with an abnormal number of chromosomes (aneuploidy). (ieo.it)
  • Condensed chromosomes attach to this framework via a specialized structure on their surface known as the kinetochore. (rupress.org)
  • Accurate chromosome segregation depends on the kinetochore, the complex of proteins that link microtubules to centromeric DNA1. (harvard.edu)
  • We studied the assembly and function of kinetochore components by fusing individual kinetochore proteins to the lactose repressor (LacI) and testing their ability to improve the segregation of a plasmid carrying tandem repeats of the lactose operator (LacO). (harvard.edu)
  • Targeting Ask1, a member of the Dam1/DASH microtubule-binding complex, creates a synthetic kinetochore that performs many functions of a natural kinetochore: it can replace an endogenous kinetochore on a chromosome, biorient sister kinetochores at metaphase of mitosis, segregate sister chromatids, and repair errors in chromosome attachment. (harvard.edu)
  • We conclude that tethering a single kinetochore protein to DNA triggers the assembly of the complex structure that directs mitotic chromosome segregation. (harvard.edu)
  • We observed that the majority of chromatids derived from micronuclei fail to establish a proper kinetochore in mitosis, which is associated with problems in chromosome alignment, segregation and spindle assembly checkpoint activation. (biologists.org)
  • We conclude that the formation of a separate small nuclear entity represents a mechanism for the cell to delay the stable propagation of excess chromosome(s) and/or damaged DNA, by inducing kinetochore defects. (biologists.org)
  • We exploit Rb fusions to study mechanisms of meiotic chromosome segregation when erroneous kinetochore-MT attachments are recognized and destabilized. (upenn.edu)
  • Loss of this force in prometaphase not only delays centrosome separation by 5-6 minutes, it also causes massive chromosome alignment and segregation defects due to the formation of syntelic and merotelic kinetochore-microtubule attachments. (biologists.org)
  • One end of each microtubule is attached to a protein-based structure called a kinetochore, which is assembled onto the centromere of each chromosome. (elifesciences.org)
  • Cancer cell lines with hyperstabilized kinetochore MTs have increased segregation errors and elevated chromosomal instability (CIN), but the genetic defects responsible remain largely unknown. (rupress.org)
  • Here we show that activation of the DNA damage response (DDR) during mitosis selectively stabilizes kinetochore-microtubule (k-MT) attachments to chromosomes through Aurora-A and Plk1 kinases, thereby increasing the frequency of lagging chromosomes during anaphase. (aacrjournals.org)
  • The accurate segregation of chromosomes requires the kinetochore, a complex protein machine that assembles onto centromeric DNA to mediate attachment of replicated sister chromatids to the mitotic spindle apparatus. (asm.org)
  • This study reveals an important role for the yeast RSC ATP-dependent chromatin-remodeling complex at the kinetochore in chromosome transmission. (asm.org)
  • Cellular surveillance pathways such as the spindle checkpoint closely monitor kinetochore-microtubule interactions to ensure that chromosome alignment, orientation, and segregation occur with fidelity ( 1 , 62 ). (asm.org)
  • Several studies in the budding yeast S. cerevisiae suggest that chromatin structure is critical for centromere-kinetochore function and chromosome segregation ( 56 , 68 ). (asm.org)
  • In this work we show that one of the components of the Saccharomyces cerevisiae kinetochore, Nkp2, plays an important role in ensuring accurate segregation of chromosomes. (springer.com)
  • Although this protein is not conserved in higher organisms, we show that it interacts with highly conserved components of the kinetochore genetically and regulates chromosome segregation. (springer.com)
  • Kinetochore clustering, frequently observed in yeasts, plays a key role in genome organization and chromosome segregation. (asm.org)
  • In the absence of the metaphase plate arrangement, kinetochore clustering in yeast species is believed to facilitate timely kinetochore-microtubule interactions to achieve bivalent attachments of chromosomes during metaphase. (asm.org)
  • Kinetochore clustering helps in the organization of yeast chromosomes in the Rabl configuration so that chromosome arms lie freely in the nucleoplasm ( 5 ). (asm.org)
  • A series of observations revealed a diverse group of proteins that contribute to the process of kinetochore clustering to ensure proper chromosome segregation. (asm.org)
  • In contrast, Caenorhabditis elegans female meiotic spindles initially shorten in the pole-to-pole axis such that spindle poles contact the outer kinetochore before the start of anaphase chromosome separation. (escholarship.org)
  • The cells depleted of Spc98 showed an aberrant kinetochore localization pattern and massive chromosome segregation errors. (asm.org)
  • The role of the kinetochore during meiotic chromosome segregation in C. elegans oocytes has been a matter of controversy. (rupress.org)
  • During mitosis, microtubules emanating from centrosomes at opposite poles of the cell bind chromosomes through a multiprotein complex called the kinetochore, allowing chromosomes to be pulled apart ( 1 , 2 ). (rupress.org)
  • showed that the kinetochore is required for chromosome alignment and congression during metaphase ( 7 ). (rupress.org)
  • However, they suggested that chromosome segregation was the result of microtubule polymerization between the segregating chromosomes ( Fig. 1 ), resulting in a pushing force exerted onto chromosomes toward the spindle poles in a largely kinetochore-independent manner ( 7 ). (rupress.org)
  • As separating chromosomes move towards the polar cortex at mid anaphase, kinetochore-localized PP1-Sds22 helps to break cortical symmetry by inducing the dephosphorylation and inactivation of ezrin/radixin/moesin proteins at cell poles. (altmetric.com)
  • In summary, this identifies a conserved kinetochore-based phosphatase signal and substrate, which function together to link anaphase chromosome movements to cortical polarization, thereby coupling chromosome segregation to cell division. (altmetric.com)
  • The kinetochore is essential for chromosome segregation and propagation of our species. (cam.ac.uk)
  • Merotelic kinetochore attachment induced by nocodazole washout leads to elevated aneuploidy of a subset of chromosomes, and high rates of anaphase lagging of chromosomes 1 and 2. (scienceopen.com)
  • They are implicated in the centrosome cycle, spindle assembly, chromosome condensation, microtubule-kinetochore attachment, the spindle checkpoint and cytokinesis. (unibas.ch)
  • Chromosome segregation is the process in eukaryotes by which two sister chromatids formed as a consequence of DNA replication, or paired homologous chromosomes, separate from each other and migrate to opposite poles of the nucleus. (wikipedia.org)
  • In a diploid cell there are two sets of homologous chromosomes of different parental origin (e.g. a paternal and a maternal set). (wikipedia.org)
  • The process of alignment of paired homologous chromosomes is called synapsis (see Synapsis). (wikipedia.org)
  • Meiotic chromosomal crossover (CO) recombination facilitates the proper segregation of homologous chromosomes. (wikipedia.org)
  • This is because, at the end of meiotic prophase I, CO recombination provides a physical link that holds homologous chromosome pairs together. (wikipedia.org)
  • Together with cohesion linkage between sister chromatids, CO recombination may help ensure the orderly segregation of the paired homologous chromosomes to opposite poles. (wikipedia.org)
  • Recombined homologous chromosomes are held together by sister chromatid cohesion after exchange of genetic material during meiotic recombination at the chiasma. (nih.gov)
  • Humans, for example, have 23 pairs of chromosomes, and the chromosomes within each pair are said to be homologous because they are similar to each other in a number of ways, including length and shape. (elifesciences.org)
  • The separation of homologous chromosomes or sister chromatids relies on them being pulled apart by microtubules. (elifesciences.org)
  • This process depends on the repair of double strand DNA breaks as crossover recombination events between homologous chromosomes, which hold homologs together to ensure their proper segregation to opposite spindle poles during the first meiotic division. (prolekare.cz)
  • It was determined that the suppression of the TRF2 expression violates the development of a compact chromocenter and the correct approach of homologous chromosomes (in germinative and somatic cells). (deepdyve.com)
  • By maintaining chiasmata, arm cohesion promotes proper orientation and microtubule attachments of homologous chromosomes on the metaphase I spindle and is therefore crucial for accurate segregation of homologs during the first meiotic division. (prolekare.cz)
  • However, because microtubules emanating from the spindle poles are not required to separate the homologous chromosomes but microtubules between the separating chromosomes are ( 8 ), this model is unlikely, at least as an explanation for mid-/late-anaphase movement. (rupress.org)
  • This telomere bouquet configuration is conserved in most eukaryotic organisms, and is thought to facilitate meiotic pairing and subsequent homologous recombination by aligning chromosomes ( 10 - 12 ). (pnas.org)
  • Using chromosomes that exhibit a high frequency of supernumerary crossovers in Caenorhabditis elegans , we find that essential chromosomal structures are mispatterned in the presence of multiple crossovers, subjecting chromosomes to improper spindle forces and leading to defects in metaphase alignment. (prolekare.cz)
  • Unequal inheritance of chromosomes (aneuploidy) is a cause of a number of disorders, particularly in humans, even though eukaryotic cells can arrest or delay the transition from metaphase to anaphase if an event critical to the completion of metaphase is impaired. (springer.com)
  • SUMMARY ANSWER Investigation of the regulatory kinase pathways involved in centromeric CPC targeting revealed normal phosphorylation dynamics of histone H2A at T120 (H2ApT120) by Bub1 kinase and subsequent recruitment of Shugoshin, but phosphorylation of histone H3 at threonine 3 (H3pT3) by Haspin failed to show the expected centromeric enrichment on metaphase chromosomes in the zygote. (eur.nl)
  • However, phosphorylation of histone H3 at threonine 3 (H3pT3) by Haspin kinase failed to show the expected centromeric enrichment on metaphase chromosomes in the zygote, but not at later stages. (eur.nl)
  • WIDER IMPLICATIONS OF THE FINDINGS In the zygote, paternal and maternal chromosomes coming from two separate pronuclei, and with contrasting epigenetic signatures, need to be aligned on a single metaphase plate. (eur.nl)
  • On the other hand, kinetochores do not cluster at any stage of the cell cycle in most metazoans, where the formation of the metaphase plate aligns all chromosomes on a single plane. (asm.org)
  • Both of these stages require chromosomes/chromatids to align during metaphase before separating to opposite poles during anaphase. (rupress.org)
  • Mammalian oocytes arrest constitutively at metaphase II in presence of aligned chromosomes, which is due to the activity of the cytostatic factor (CSF). (uni-bielefeld.de)
  • Interestingly, noncoding RNA (RNA that does not make proteins) in fission yeast transcribed from the chromosome centromere is necessary for the formation of heterochromatin in the centromere itself. (eurekalert.org)
  • Now, a study published by Cell Press in the April 29th issue of the journal Cell , provides fascinating new insight into the complex of proteins that orchestrates the proper segregation of human chromosomes during cell division. (scienceblog.com)
  • During the process of mitosis, DNA and its associated packing proteins are arranged into structures called chromosomes that are duplicated and then segregated. (scienceblog.com)
  • At mitotic entry, kinetochores assemble on the centromeres (CEN) of the replicated chromosomes (sister chromatids) to bi-orient them on the mitotic spindle, a dynamic array of centrosomes (spindle poles), microtubules and microtubule-associated proteins. (ieo.it)
  • Following satisfaction of the SAC and separation of all bi-oriented sisters (by dissolution of the cohesion linkages), kinetochores, motor proteins and spindle regression move the chromosomes into the daughter cells, generating offspring with a correct number of chromosomes. (ieo.it)
  • Using yeast allows for a quick genetic identification of proteins involved in chromosome segregation and for dissecting functional relationships between the involved proteins. (ieo.it)
  • Besides kinetochores we also study proteins regulating rDNA segregation in Saccharomyces cerevisiae . (ieo.it)
  • To identify new proteins involved in chromosome segregation we perform protein affinity purifications and yeast two-hybrid screens. (ieo.it)
  • Inhibition of DDR proteins, ATM or Chk2, abolishes the effect of DNA damage on k-MTs and chromosome segregation, whereas activation of the DDR in the absence of DNA damage is sufficient to induce chromosome segregation errors. (aacrjournals.org)
  • MAIN RESULTS AND THE ROLE OF CHANCE Immunofluorescent analysis of the CPC subunit Inner Centromere Protein revealed the pool of stably bound CPC proteins was not strictly confined to the inner centromere of prometaphase chromosomes in human zygotes, as observed in later stages of preimplantation development and somatic cells. (eur.nl)
  • When we reduce the proteins responsible for rejuvenation after meiotic S phase, cohesion is lost and meiotic chromosomes missegregate. (prolekare.cz)
  • Saccharomyces cerevisiae kinesin- and dynein-related proteins required for anaphase chromosome segregation. (rupress.org)
  • In this study, the roles of these motor proteins in anaphase chromosome segregation were examined. (rupress.org)
  • A complex between the anaphase promoting factor/cylosome (APC/C), its accessory protein Cdc20 and proteins of the SAC renders APC/C inactive, usually until all chromosomes are properly assembled at the spindle equator (chromosome congression) and under tension from spindle fibres. (uni-bielefeld.de)
  • The findings reveal the proteins' significance in the correct segregation of X-shaped chromosomes - packages of DNA made up of two strands of identical genetic information. (ed.ac.uk)
  • Further analysis revealed that these three proteins are not only essential but also sufficient to maintain the centromere mark on chromosomes from one cell generation to the next. (ed.ac.uk)
  • In addition to ParABS systems, most bacteria harbor condensin complexes, members of the structural maintenance of chromosomes (SMCs) family of proteins found in all kingdoms of life 23 . (nature.com)
  • Harms, et al , 1 used YFP- and mCherry-labeled proteins that bind to specific regions of the chromosome during replication to visualize where the chromosome localizes at different points in the cell cycle. (hamamatsu.com)
  • This work demonstrates that a subset of the CCAN proteins, which form the CENP-T pathway, dominates to ensure successful cell division by binding to a protein complex called the Ndc80 complex, which allows microtubules to attach to chromosomes. (somefind.com)
  • The process of division in bacterial chromosomes is regulated by the Par (partition) proteins, which bind to DNA. (sheffield.ac.uk)
  • The project combines multidisciplinary approaches including biochemistry, single-molecule fluorescence microscopy and bionanotechnology to visualize the chromosome segregation proteins on synthetic surfaces in a cell-free system. (sheffield.ac.uk)
  • Acetylation of histone proteins in chromosomes tends to activate genes or facilitate transcription of genes into mRNA and translation of mRNA into protein. (wcrf.org)
  • Numerous proteins are implicated in co-replicational DNA segregation and they will be characterized in this review. (edu.pl)
  • The proteins SeqA, SMC/MukB, MinCDE, MreB/Mbl, RacA, FtsK/SpoIIIE playing different roles in bacterial cells are also involved in chromosome segregation. (edu.pl)
  • The chromosomally encoded ParAB homologs of active partitioning proteins of low-copy number plasmids are also players, not always indispensable, in the segregation of bacterial chromosomes. (edu.pl)
  • Microtubules nucleated from the centrosomes (yellow) oscillate between phases of growth and shrinkage `searching' for chromosomes. (nih.gov)
  • In cell-free Xenopus extracts, microtubules are nucleated in the vicinity of chromatin-coated beads in random orientation and are subsequently sorted into an antiparallel microtubule array that surrounds chromosomes. (nih.gov)
  • A motorless version of MCAK that binds centromeres but not microtubules disrupts chromosome segregation during anaphase. (rupress.org)
  • At the onset of mitosis, cells need to break down their nuclear envelope, form a bipolar spindle and attach the chromosomes to microtubules via kinetochores. (biologists.org)
  • The dynamic regulation of microtubules (MTs) during mitosis is critical for accurate chromosome segregation and genome stability. (rupress.org)
  • It was surprising that actin fibers are also involved in segregating chromosomes in eggs, because chromosome segregation is generally thought to rely solely on another type of protein fiber, called microtubules, which make up the spindle. (mpg.de)
  • Microtubules segregate chromosomes by attaching to macromolecular kinetochores. (elifesciences.org)
  • Using this information it was possible to investigate the function of the two different pools of BubR1 and show that one pool helps establish the connection between kinetochores and microtubules and the other pool controls when the chromosomes should split into the two new daughter cells. (ku.dk)
  • Co-immunoprecipitation experiments showed that satellite I RNA associates with Aurora B, a component of the chromosome passenger complex (CPC) regulating proper attachment of microtubules to kinetochores, in mitotic HeLa cells. (ovid.com)
  • In cell division, microtubules can physically manipulate the chromosomes, pull half of each chromosome for transposition into a daughter cell and half in the other. (somefind.com)
  • Our model reveals that successful cell division requires control of the total number of microtubules: if this number is too small bi-orientation fails, while if it is too large not all the chromosomes are able to congress. (aalto.fi)
  • What causes this high error rate is unknown, as mechanisms used to ensure proper chromosome segregation in mammalian embryos are poorly described. (eur.nl)
  • Thus, laggards and micronuclei are indicators of chromosome missegregation and aneuploidy. (jneurosci.org)
  • As most solid tumors are aneuploid it has been hypothesized that chromosome missegregation drives or supports the cancer transformation process. (ieo.it)
  • Hepatocytes proliferating in regenerating livers, such as the mitotic cell shown here with a mitotic spindle (green) capturing chromosomes (blue), are able to accurately segregate chromosomes, whereas hepatocytes dividing in culture have high levels of chromosome missegregation. (mit.edu)
  • Reducing GTSE1 levels in CIN cancer cell lines reduces chromosome missegregation defects, whereas artificially inducing GTSE1 levels in chromosomally stable cells elevates chromosome missegregation and CIN. (rupress.org)
  • Both sth1 and sfh1 mutants exhibit altered centromeric and centromere-proximal chromatin structure and increased missegregation of authentic chromosomes. (asm.org)
  • Overexpression of the full-length DIS2S1/GLC7 gene results in chromosome missegregation in wild-type cells and exacerbates the mutant phenotype in ipl1 cells. (asm.org)
  • The deregulation of Aurora kinases impairs spindle assembly, checkpoint function and cell division, causing missegregation of individual chromosomes or polyploidization accompanied by centrosome amplification. (unibas.ch)
  • Furthermore , germline expression of a truncated dRING molecule that contains the ORD-interaction domain enhances levels of chromosome missegregation in ord mutant males and females . (dartmouth.edu)
  • Professor Tokio Tani's research group in Kumamoto University found that a mutation in the protein Prp16, which is involved in the splicing reaction that removes intron sequences, makes it impossible to accurately separate chromosomes during cell division. (eurekalert.org)
  • CAMBRIDGE, Mass. (November 19, 2015) - Whitehead Institute researchers have revealed the architecture of a protein complex that plays a foundational role in the machine that directs chromosome segregation during cell division. (eurekalert.org)
  • Chromosome segregation and cell division are essential, highly ordered processes that depend on numerous protein complexes. (nih.gov)
  • Using gene tagging on bacterial artificial chromosomes, protein localization, and tandem-affinity purification-mass spectrometry, the MitoCheck consortium has analyzed about 100 human protein complexes, many of which had not or had only incompletely been characterized. (nih.gov)
  • In the majority of bacterial species, faithful chromosome segregation is mediated by the tripartite ParABS system, consisting of an ATPase protein ParA, a CTPase and DNA-binding protein ParB, and a centromere-like parS site. (jic.ac.uk)
  • The architectural protein H-NS binds nonspecifically to hundreds of sites throughout the chromosome and can multimerize to stiffen segments of DNA as well as to form DNA-protein-DNA bridges. (asm.org)
  • Scientists at the Max Planck Institute (MPI) for Biophysical Chemistry now show in the mouse model that the structural protein actin protects egg cells from mistakes during chromosome segregation. (mpg.de)
  • Here we report two replication-control mechanisms mediated by a chromosome segregation protein, ParB2, encoded by chromosome II of the model multichromosome bacterium, Vibrio cholerae. (epfl.ch)
  • The 39- mers are the strongest inhibitors of chromosome II replication and they mediate inhibition by binding the replication initiator protein. (epfl.ch)
  • Postdoc Gang Zhang investigated how the BubR1 protein functions in the cell, particularly its role at a structure on chromosomes called kinetochores. (ku.dk)
  • Type 1 protein phosphatase acts in opposition to IpL1 protein kinase in regulating yeast chromosome segregation. (asm.org)
  • Conditional ipl1ts mutants missegregate chromosomes severely at 37 degrees C. Here, we report that IPL1 encodes an essential putative protein kinase whose function is required during the later part of each cell cycle. (asm.org)
  • In an effort to identify additional gene products that participate with the Ipl1 protein kinase in regulating chromosome segregation in yeast, a truncated version of the previously identified DIS2S1/GLC7 gene was isolated as a dosage-dependent suppressor of ipl1ts mutations. (asm.org)
  • These results suggest that type 1 protein phosphatase acts in opposition to the Ipl1 protein kinase in vivo to ensure the high fidelity of chromosome segregation. (asm.org)
  • In the present study, reasons for the high frequency of chromosome nondisjunction were studied among descendants of mutants from 18 lines with a decreased expression of the TRF2 protein. (deepdyve.com)
  • This mechanism was also supported by the finding that CLIP-associated protein (CLASP)-dependent microtubule polymerization between the segregating chromosomes is essential for chromosome separation ( 8 ). (rupress.org)
  • FtsK is a 1329 amino acid protein involved in bacterial cell division and chromosome segregation. (wikipedia.org)
  • Found at the cytoplasmic end of the linker domain, the FtsKC segment of the protein is responsible for enabling the activity of the Xer recombination system upon the formation of a chromosome dimer. (wikipedia.org)
  • Human-chromatin-related protein interactions identify a demethylase complex required for chromosome segregation. (ac.be)
  • A new study is reported in the newspaper nature Cell Biology has gained insight into this process by revealing the details of how protein complexes coincide at the center of chromosomes in places called centromerrals. (somefind.com)
  • At these sites, the protein complexes function as anchors through which cellular structural organizers can redistribute chromosomes in the cell. (somefind.com)
  • Future studies will be carried out on understanding how similar protein patterns drive chromosome segregation in bacteria. (sheffield.ac.uk)
  • Kovacikova I, Polakova S, Benko Z, Cipak L, Zhang L, Rumpf C, Miadokova E, Gregan J (2013) A knockout screen for protein kinases required for the proper meiotic segregation of chromosomes in the fission yeast Schizosaccharomyces pombe. (edu.pl)
  • In the fission yeast Schizosaccharomyces pombe , silencing factors such as the heterochromatin protein 1 homolog Swi6, the histone H3 Lys-9 methyltransferase Clr4, and histone deacetylases are required for centromere function and chromosome segregation ( 1 , 4 , 5 ). (pnas.org)
  • Aussel L, Barre F-X, Aroyo M, Stasiak A, Stasiak AZ, Sherratt D. (2002) FtsK is a DNA motor protein that activates chromosome dimer resolution by switching the catalytic state of the XerC and XerD recombinases. (edu.pl)
  • Ben-Yehuda S, Rudner DZ, Losick R. (2003) RacA, a bacterial protein that anchors chromosomes to the cell poles. (edu.pl)
  • 1998) Characterization of a prokaryotic SMC protein involved in chromosome partitioning. (edu.pl)
  • 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 . (dartmouth.edu)
  • In order for chromosomes to equally divide, it is necessary first to bind the filamentous spindle fiber to a specific region, the centromere, of the chromosome. (eurekalert.org)
  • They examined why splicing mutants show chromosome segregation abnormalities and found that splicing mutant strains do not normally form heterochromatin in the chromosome centromere region. (eurekalert.org)
  • Duplicated chromosomes are attached together at a region called the centromere. (scienceblog.com)
  • Karyotype conversion, from mostly telocentric (centromere terminal) to mostly metacentric (centromere internal), typically reflects fixation of Robertsonian (Rb) fusions, a common chromosomal rearrangement that joins two telocentric chromosomes at their centromeres to create one metacentric. (upenn.edu)
  • Centromere function in the budding yeast Saccharomyces cerevisiae is conferred by an unusually compact 125-bp DNA sequence comprised of three conserved elements, CDEI, CDEII, and CDEIII, which are necessary and sufficient to mediate segregation of sister chromatids ( 12 , 29 ). (asm.org)
  • The centromere is found where identical chromosome strands are tethered together and forms a point of attachment for long fibres, called the mitotic spindle, that pull them apart as the cell divides. (ed.ac.uk)
  • Scientists at the University of Edinburgh sought to better understand how the centromere is assembled and targeted to the correct position in specific sections of chromosomes. (ed.ac.uk)
  • Chromosome conformation capture reveals SMC-mediated long-range interactions around ten centromere-like parS sites clustered at the replication origin ( oriC ). (nature.com)
  • In Drosophila oocytes, microtubule asters first assemble at NEBD away from chromosomes in the absence of discrete PCM-containing MTOCs. (nih.gov)
  • Knockdown of Gie in Drosophila cells also blocked normal sister chromosome segregation but did not block the progression of mitosis. (sciencemag.org)
  • Male Drosophila lack synapsis, but nonetheless, their chromosomes closely associate with the nuclear periphery at prophase I. To explore the functional significance of this association, we characterize mutations in nuclear blebber ( nbl ), a gene required for both spermatocyte nuclear shape and meiotic chromosome transmission. (genetics.org)
  • The association of meiotic chromosomes with the nuclear periphery is particularly striking in Drosophila males, in which paired homologs occupy discreet domains closely apposed to the nuclear membrane. (genetics.org)
  • Double or nothing: a Drosophila mutation affecting meiotic chromosome segregation in both females and males. (genetics.org)
  • Escherichia coli cells depleted of the conserved GTPase, ObgE, show early chromosome-partitioning defects and accumulate replicated chromosomes in which the terminus regions are colocalized. (wiley.com)
  • Here we report the identification of chromosomal segregation defects in normal NPCs of the mouse cerebral cortex. (jneurosci.org)
  • These data independently confirm the presence of aneuploid NPCs and demonstrate the occurrence of mitotic segregation defects in normal cells that can mechanistically account for aneuploidy in the CNS. (jneurosci.org)
  • Cells lacking GTSE1 have defects in chromosome alignment and spindle positioning as a result of MT instability caused by excess MCAK activity. (rupress.org)
  • These defects frequently give rise to eggs with an incorrect number of chromosomes," Schuh comments on her department's latest research findings. (mpg.de)
  • Additionally, the chromosomes with extra interfering crossovers often exhibited segregation defects in anaphase I, with a high incidence of chromatin bridges that sometimes created a tether between the chromosome and the first polar body. (prolekare.cz)
  • Finally, inhibiting the DDR during mitosis in cancer cells with persistent DNA damage suppresses inherent chromosome segregation defects. (aacrjournals.org)
  • Importantly, it is currently unknown whether the defects in SCC in Tex19.1-/- ES cells are also caused by changes in AcSMC3, and if increased aneuploidy is caused by chromosome mis-segregation. (ed.ac.uk)
  • Defects in mitotic chromosome segregation are correlated with loss of cohesin at centromeres. (pnas.org)
  • Using fluorescence in situ hybridization (FISH) , we show that defects in centromeric cohesion manifest during late G2 in spermatocytes that lack ORD activity and are extensive after prophase I chromosome condensation . (dartmouth.edu)
  • They then analyzed the cause of abnormality of centromeric heterochromatin formation in splicing mutant strain, showing that introns in nontranslatable RNA are transcribed from chromosome centromeres, and that artificial removal of introns induced abnormalities in heterochromatin formation. (eurekalert.org)
  • This study revealed for the first time that intron sequences, originally thought to be useless sequences that were normally removed in the process of gene expression, have an important function of controlling heterochromatin formation in chromosome centromeres. (eurekalert.org)
  • Kinetochores are macromolecular proteinaceous assemblies that are assembled on centromeres and attach chromosomes to the spindle fibres and regulate the accurate transmission of genetic material to daughter cells. (springer.com)
  • Here, using fluorescence In-Situ hybridization (FISH) imaging of specific centromeres coupled with high-throughput single cell analysis, as well as single-cell sequencing we show that human chromosome mis-segregation is non-random. (scienceopen.com)
  • In a variety of systems, mutants that affect the formation of heterochromatin within centromeres adversely affect chromosome segregation ( 1 - 3 ). (pnas.org)
  • Partitioning bacterial chromosomal DNA into many small volumes during dPCR enabled AST results after short exposure times by 1) precise quantification and 2) a measurement of how antibiotics affect the states of macromolecular assembly of bacterial chromosomes. (caltech.edu)
  • Most bacterial chromosomes and low copy number plasmids encode an active segregation machinery called ParABS to partition replicated DNA prior to cell division. (sheffield.ac.uk)
  • The authors used numerical simulations to demonstrate that entropy alone is not sufficient to complete segregation of bacterial chromosomes. (dkfz.de)
  • Our findings indicate that the bulk of anaphase chromosome segregation in S. cerevisiae is accomplished by the combined actions of these three motors. (rupress.org)
  • In the pre-implantation embryo, aneuploidy resulting from chromosome segregation error is considered responsible for pregnancy loss. (nature.com)
  • Through live-cell imaging, single embryo transfer, and genome sequencing at single-cell resolution, we demonstrated that early chromosomal segregation error resulting in aneuploidy in mouse pre-implantation embryos is a developmental risk to the blastocyst, but some blastocysts retain their developmental potential. (nature.com)
  • Other errors can result in the chromosomes being unevenly divided between daughter cells, a condition called aneuploidy. (mit.edu)
  • You are cordially invited to the EMBO Workshop on Chromosome Segregation and Aneuploidy, to be held on June 22-26, 2013, on the estate of Nyenrode Castle in Breukelen, The Netherlands. (biotechsciencenews.com)
  • Human chromosomes vary widely in size, gene density and other parameters that might generate bias in mis-segregation rates, however technological limitations have precluded a systematic and high throughput analysis of chromosome-specific aneuploidy. (scienceopen.com)
  • Our findings suggest that inherent properties of specific chromosomes can influence chromosome mis-segregation and aneuploidy, with implications for studies on aneuploidy in human disease. (scienceopen.com)
  • When an egg is fertilized by a sperm, maternal and paternal chromosomes unite - a new life begins. (mpg.de)
  • Our results suggest that adaptations in mechanisms regulating CPC targeting exist in the human zygote, to ensure symmetric recruitment despite the epigenetic asymmetry between maternal and paternal chromosomes. (eur.nl)
  • This division segregates maternal and paternal chromosomes for production of eggs and sperms, which are the origin of a new life. (riken.jp)
  • The finding is expected to lead to the clarification of development mechanisms of diseases caused by abnormalities in the number of chromosomes, such as Down syndrome. (eurekalert.org)
  • Understanding the mechanisms that coordinate replication initiation with subsequent segregation of chromosomes is an important biological problem. (epfl.ch)
  • We suggest that both these are novel mechanisms to coordinate replication initiation with segregation of chromosomes. (epfl.ch)
  • The aim of this project is to gain insight into the molecular mechanisms underpinning bacterial chromosome segregation. (sheffield.ac.uk)
  • This book describes current knowledge about the mechanisms by which cells segregate their already duplicated chromosomes in preparation for cell division. (topfreebooks.org)
  • Whether bacteria segregate their chromosomes by passive or active mechanisms has been a long-standing debate. (dkfz.de)
  • A low concentration of CENP-E inhibitor (CENP-Ei) inhibits chromosome congression, causing misalignment of one or few chromosomes. (biologists.org)
  • Constitutive Astrin:PP1-delivery disrupts chromosome congression and segregation, revealing a dynamic mechanism for stabilising attachments. (elifesciences.org)
  • While a multitude of biological factors regulating chromosome congression and bi-orientation have been identified, it is still unclear how they are integrated so that coherent chromosome motion emerges from a large collection of random and deterministic processes. (aalto.fi)
  • Here we address this issue by a three dimensional computational model of motor-driven chromosome congression and bi-orientation during mitosis. (aalto.fi)
  • During mitosis, kinetochores orchestrate chromosome transmission from the mother into the daughter cells. (ieo.it)
  • The attachment of chromosomes to the mitotic spindle is mediated by kinetochores, multiprotein complexes that assemble onto centromeric DNA. (asm.org)
  • It represents a surveillance mechanism that halts cells in M-phase in the presence of unattached chromosomes, associated with accumulation of checkpoint components, in particular, Mad2, at the kinetochores. (uni-bielefeld.de)
  • Faithful segregation of genetic material during cell division requires alignment of chromosomes between two spindle poles and attachment of their kinetochores to each of the poles. (aalto.fi)
  • During anaphase I, dissolution of chromosome arm cohesion leads to reductional segregation of homologs. (nih.gov)
  • 8. Martinez-Perez E, Schvarzstein M, Barroso C, Lightfoot J, Dernburg AF, Villeneuve AM. Crossovers trigger a remodeling of meiotic chromosome axis composition that is linked to two-step loss of sister chromatid cohesion. (prolekare.cz)
  • Sister chromatid cohesion is first established during DNA replication or shortly thereafter and is maintained as chromosomes condense and align themselves on the mitotic spindle until the onset of anaphase. (asm.org)
  • Sister chromatid cohesion and segregation is a critical step for guaranteeing the equal distribution of genetic materials between daughter cells. (plantcell.org)
  • In both mitotic and meiotic cells, sister chromatid cohesion is required for accurate chromosome segregation, and the cohesive linkages that hold sister chromatids together depend on the cohesin complex which forms a DNA-entrapping ring [1] , [2] . (prolekare.cz)
  • The age-related reduction in expression of components of the SAC in mammalian oocytes may act synergistically with spindle and other cell organelles' dysfunction, and a partial loss of cohesion between sister chromatids to predispose oocytes to errors in chromosome segregation. (uni-bielefeld.de)
  • Mechanistically, we show that these chromosomes are prone to cohesion fatigue that results in anaphase lagging upon release from nocodazole or Eg5 inhibition. (scienceopen.com)
  • In this review, we examine the role of the ubiquitin system in the events relating to centriole duplication and centrosome separation, and discuss how the disruption of these functions impacts chromosome segregation. (elsevier.com)
  • Abnormal chromosomal segregation, on the other hand, can cause cell death (apoptosis) or diseases like Down syndrome and cancer. (eurekalert.org)
  • Furthermore, the severity of chromosomal segregation errors ranges from mild, where the chromosome deviates a few micrometers from the others, to severe with micronuclei formation. (nature.com)
  • Using our less-invasive live-cell imaging system optimized for long-term imaging for the analysis of molecular dynamics of mammal pre-implantation embryos 12 , the type/severity of early chromosomal segregation errors in pre-implantation embryos can be assessed. (nature.com)
  • We performed embryo transfer after fluorescence observation of chromosomal segregation using mouse embryos obtained by in vitro fertilization (IVF) (a technique where unfertilized eggs retrieved from females are fertilized in vitro with spermatozoa). (nature.com)
  • 1991) Escherichia coli XerC recombinase is required for chromosomal segregation at cell division. (edu.pl)
  • Microtubule (−)-ends are focused away from chromosomes to form the spindle poles. (nih.gov)
  • In the 'extrusion-capture' model, replication through an anchored replisome provides the force to move daughter chromosomes to the poles ( Lemon and Grossman, 2001 ). (wiley.com)
  • Moreover, in these cells, chromosomes are often retained at the spindle poles and do not correctly move to the center. (mpg.de)
  • In a wide range of eukaryotes, chromosome segregation occurs through anaphase A, in which chromosomes move toward stationary spindle poles, anaphase B, in which chromosomes move at the same velocity as outwardly moving spindle poles, or both. (escholarship.org)
  • The spindle shortens an additional 0.5 μm until the chromosomes are embedded in the spindle poles. (escholarship.org)
  • Chromosomes then separate at the same velocity as the spindle poles in an anaphase B-like movement. (escholarship.org)
  • We conclude that the majority of meiotic chromosome movement is caused by shortening of the spindle to bring poles in contact with the chromosomes, followed by separation of chromosome-bound poles by outward sliding. (escholarship.org)
  • This segregation event takes place in two stages: anaphase A, where chromosomes are pulled toward spindle poles due to microtubule depolymerization, and anaphase B, where spindle poles themselves move farther apart, taking the attached chromosomes with them ( 3 , 4 ). (rupress.org)
  • An alternative model suggested that chromosomes are transported through microtubule-free channels toward the spindle poles by the action of dynein ( 9 ). (rupress.org)
  • Later evidence put in doubt a role for dynein and favored a model in which chromosomes initially separate when the spindle shortens and the poles overlap with chromosomes in an anaphase A-like mechanism. (rupress.org)
  • This is then followed by separation of chromosome-bound poles by outward microtubule sliding in an anaphase B-like fashion ( 10 ). (rupress.org)
  • Repeated binding and unbinding of chromosomal segments to these tethering sites eventually can mediate segregation of sister chromosomes by biasing their random movement toward the poles in a Brownian ratchet-like manner. (dkfz.de)
  • 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 . (dartmouth.edu)
  • This suggests the possibility that such a system could be used to generate human artificial chromosomes. (scienceblog.com)
  • During this stage, segregation occurs by a process similar to that during mitosis, except that in this case prophase II is not preceded by a round of DNA replication. (wikipedia.org)
  • Failure of proper segregation during prophase II can also lead to aneuploid gametes. (wikipedia.org)
  • In many organisms, homolog pairing and synapsis at meiotic prophase depend on interactions between chromosomes and the nuclear membrane. (genetics.org)
  • ASSOCIATIONS between chromosomes and the nuclear envelope during meiotic prophase are a widely conserved phenomenon important for proper chromosome transmission. (genetics.org)
  • However, only a few studies have examined the relationship between chromosome segregation errors during early cleavage and development. (nature.com)
  • An increased number of aneuploid blastomeres in embryos may result from chromosome segregation errors during early division. (nature.com)
  • To test whether our de novo- induced micronucleated cells displayed higher amounts of chromosome segregation errors than cells with a single nucleus, we scored segregation errors by live-cell imaging of the mitosis following micronucleus formation ('2nd division', see Fig. 1 A for experimental setup). (biologists.org)
  • In reality, there are sometimes errors in the process of separating chromosomes into daughter cells, known as chromosome mis-segregation. (mit.edu)
  • Low tension is a widely accepted mechanism for recognizing errors, but whether chromosome position regulates MT attachments is unknown. (upenn.edu)
  • Persistent errors in chromosome segregation lead to chromosomal instability (CIN), the increased rate of gain or loss of chromosomes within a cell population. (rupress.org)
  • Oocytes with reduced actin tend to have chromosome segregation errors. (mpg.de)
  • In the future, we want to find out whether actin also protects human eggs from chromosome segregation errors," Schuh says. (mpg.de)
  • Actin protects mammalian eggs against chromosome segregation errors. (mpg.de)
  • The cells in the dek15 endosperm and embryo exhibited precocious sister chromatid separation and other chromosome segregation errors, including misaligned chromosomes, lagging chromosomes, and micronuclei, resulting in a high percentage of aneuploid cells. (plantcell.org)
  • In a woman's thirties, errors in meiotic chromosome segregation rise exponentially, significantly increasing the probability that she will conceive a fetus with Down Syndrome (Trisomy 21). (prolekare.cz)
  • The findings are important for the understanding of chromosome errors in human eggs. (riken.jp)
  • For over a century, the abnormal movement or number of centrosomes has been linked with errors of chromosomes distribution in mitosis. (elsevier.com)
  • I compared the incidence of errors commonly associated with chromosome mis-segregation between Tex19.1-/- and control cells, and found an increase in micronuclei in interphase Tex19.1-/- ES cells. (ed.ac.uk)
  • My data supports the model that loss of Tex19.1 in ES cells causes changes in the amount of AcSMC3 associated with chromatin, and errors in chromosome segregation. (ed.ac.uk)
  • Expression of a dominant-negative form of Gie1 in a cultured human cell line caused the appearance of micronuclei and abnormal chromosome segregation. (sciencemag.org)
  • These results suggest that early chromosome segregation error causing micronuclei formation affects ploidy and development to blastocyst but does not necessarily cause developmental failure after the blastocyst stage. (nature.com)
  • The presence of micronuclei is a hallmark of chromosome instability. (biologists.org)
  • Figure: Localization of BubR1 (red) on chromosomes (blue) during cell division. (ku.dk)
  • In addition, further research is needed to determine to what extent the differences we observed in H3T3 phosphorylation dynamics and CPC localization affect chromosome attachment. (eur.nl)
  • These results suggest that satellite I RNA is involved in chromosome segregation through controlling activity and centromeric localization of Aurora B kinase. (ovid.com)
  • The researchers determined the architecture of the ancestral SMC complex and elucidated its dynamic localization on the bacterial chromosome. (mpg.de)
  • We suggest that dtopors plays a structural role in spermatocyte lamina that is critical for multiple aspects of meiotic chromosome transmission. (genetics.org)
  • These data suggest that the TLSPs contribute to multiple aspects of meiotic chromosome dynamics. (caltech.edu)
  • All growth and reproduction relies on a cell's ability to replicate its chromosomes and produce accurate copies of itself. (mit.edu)
  • The precise regulation of microtubule (MT) dynamics is essential to the accurate execution of mitosis and the faithful segregation of chromosomes. (rupress.org)
  • As the removal of H3pT3 from the chromosome arms during prometaphase normally contributes to further centromeric enrichment of the CPC in somatic cells, CPC targeting may be less accurate in human zygotes. (eur.nl)
  • We find that the RNAi machinery is required for the accurate segregation of chromosomes. (pnas.org)
  • Phenotypic effects of mutations on chromosome segregation and mitosis are studied in synchronous cell cycles by indirect immunofluorescence microscopy, chromosome spreads, study of sister chromatid alignment using integrated pericentromeric GFP arrays, and FACS analysis (to probe the DNA status of the cells). (ieo.it)
  • Therefore, the bacterial Min system coordinates cell division and chromosome segregation. (dkfz.de)
  • This work has led to the discovery of previously unknown, evolutionarily conserved subunits of the anaphase-promoting complex and the gamma-tubulin ring complex--large complexes that are essential for spindle assembly and chromosome segregation. (nih.gov)
  • in this study, ploidy of blastomeres of 2-cell embryos was investigated by single-cell genome sequencing after live-cell imaging of 1st mitosis to link the imaging data of chromosome segregation and ploidy of embryo. (nature.com)
  • Hence, the segregation of the genome is coordinated in time and space. (ieo.it)
  • The segregation of sister chromatids during cell division ensures that each daughter cell receives a complete copy of the genome. (asm.org)
  • During the construction of yeast artificial chromosome (YAC) libraries to facilitate mapping of the human genome, two YACs may be cotransformed into the same yeast cell, making further analysis very difficult. (ox.ac.uk)
  • The selective chromatid segregation model has been proposed as a mechanism for the asymmetric cell division that initiates a cascade of gene regulation events in offspring cells to develop brain laterality in embryogenesis. (omicsonline.org)
  • The regulation of higher-order chromosome structure is central to cell division and sexual reproduction. (pnas.org)
  • The dynamic regulation of chromosome structure governs diverse cellular processes. (pnas.org)
  • This equal distribution of chromosomes is very important to accurately pass on genetic information to the next generation. (eurekalert.org)
  • We have argued that chromosome 11 translocations associated with psychosis found in three families provide the only convincing evidence for the genetic etiology of psychosis. (omicsonline.org)
  • Spindle formation, chromosome segregation and the spindle checkpoint in mammalian oocytes and susceptibility to meiotic error", MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS , vol. 651, 2008, pp. 14-29. (uni-bielefeld.de)
  • In general, the chromosome dimer is translocated so that the site of resolution is near the divisome and so one copy of the genetic material ends up in each daughter cell. (wikipedia.org)
  • In citrus, a classical method of studying crossovers and segregation distortion (SD) is the genetic analysis of progenies. (frontiersin.org)
  • 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 . (dartmouth.edu)
  • The Dynamics of Message Selection in Online Political Discussion Forums: Self-Segregation or Diverse Exposure? (escholarship.org)
  • Tracking of Chromosome and Replisome Dynamics in Myxococcus xanthus Reveals a Novel Chromosome Arrangement. (hamamatsu.com)
  • Although molecular dynamics simulation and a simulation combined with randomly swapping atoms and vacancies have usually been used to investigate the segregation structures, they require more than ten thousand structures and energy calculations to reach the stable configuration. (bioportfolio.com)
  • In addition to telomere maintenance, the formation of specialized structures at telomeres plays a crucial role in telomeric clustering and chromosome dynamics in fission yeast ( 6 - 9 ). (pnas.org)
  • These connections establish bridges across the nuclear envelope and allow for interactions between meiotic chromosomes and cytoskeletal actin. (genetics.org)
  • I think the assumption was … a cell would segregate chromosomes the same way in a dish as it would in a tissue because everything was happening inside the cell. (mit.edu)
  • The spindle is an apparatus that segregate chromosomes into the egg. (riken.jp)
  • The IPL1 gene is required for high-fidelity chromosome segregation in the budding yeast Saccharomyces cerevisiae. (asm.org)
  • The asymmetrically dividing budding yeast, _Saccharomyces cerevisiae_, relies upon alignment of the mitotic spindle along the mother-to-daughter cell polarity axis for the fidelity of chromosome segregation. (bilkent.edu)
  • Recent advances in the analysis of the role of SUMO (small ubiquitin-like modifier) and in the identification of SUMO-modified targets indicate that sumoylation is likely to have several key roles in regulating chromosome segregation This mini-review summarises the recently published data concerning the role of SUMO in the processes required for efficient chromosome segregation. (nih.gov)
  • Here, we review the various models for the formation of the ParABS complex and describe its role in segregating the origin-proximal region of the chromosome. (jic.ac.uk)
  • The tight choreography requires that each region of the chromosome moves to a specific part of the cell at precisely defined times during the cell cycle. (hamamatsu.com)
  • Sad1 is nonessential for viability in C. neoformans but is required for proper growth and high-fidelity chromosome segregation. (asm.org)
  • In mouse oocytes, multiple MTOCs (yellow) assemble microtubule aster-like structures in the vicinity of chromosomes that subsequently are organized into a bipolar spindle. (nih.gov)
  • The precursor cells of eggs, the so-called oocytes, harbor - as all other cells in our body - two copies of each chromosome. (mpg.de)
  • Vogt E, Kirsich-Volders M, Parry J, Eichenlaub-Ritter U. Spindle formation, chromosome segregation and the spindle checkpoint in mammalian oocytes and susceptibility to meiotic error. (uni-bielefeld.de)
  • My findings also indicate that ES cells may be a more tractable cellular model than mouse oocytes to analyse the role of TEX19.1 and AcSMC3 on chromosome segregation. (ed.ac.uk)
  • H-NS has been suggested to contribute to the orderly folding of the Escherichia coli chromosome in the highly compacted nucleoid. (asm.org)
  • The Xer site-specific recombination system functions in Escherichia coli to ensure that circular plasmids and chromosomes are in the monomeric state prior to segregation at cell division. (gla.ac.uk)
  • Much of the previous work on bacterial replication and chromosome segregation has focused on Caulobacter crescentus , Escherichia coli , and Pseudomonas aeruginosa , with the finding that the mechanics of the process differs among different bacterial species. (hamamatsu.com)
  • They find that, in Escherichia coli , the oscillating Min system mediates a novel Brownian ratchet-type mechanism of chromosome segregation, challenging the conventional view that the Min system only functions in mid-cell determination. (dkfz.de)
  • Chromosome segregation by the Escherichia coli Min system. (dkfz.de)
  • Upon proper segregation, a complete set of chromatids ends up in each of two nuclei, and when cell division is completed, each DNA copy previously referred to as a chromatid is now called a chromosome. (wikipedia.org)
  • Proper chromosome segregation during cell division is essential in all domains of life. (jic.ac.uk)
  • Finally, RSC is not required for centromeric deposition of the histone H3 variant Cse4p, suggesting that RSC plays a role in reconfiguring centromeric and flanking nucleosomes following Cse4p recruitment for proper chromosome transmission. (asm.org)
  • Thus, Astrin-PP1 mediates a dynamic 'lock' that selectively and rapidly stabilises end-on attachments, independent of biorientation, and ensures proper chromosome segregation. (elifesciences.org)
  • Sad1 is required for proper chromosome segregation. (asm.org)
  • This tension is required for proper bi-orientation of sister chromosomes as well as for satisfaction of the spindle assembly checkpoint and entry into anaphase. (cam.ac.uk)
  • Our work disappears from a previous consensus by demonstrating that it is CENP-T, not CENP-C, which acts through the Ndc80 complex for successful cell division by ensuring proper and fast chromosome segregation,' says principal author Masatoshi Hara. (somefind.com)
  • Research reveals that the external environment of epithelial cells influences the fidelity of chromosome segregation. (mit.edu)
  • In most bacteria two vital processes of the cell cycle: DNA replication and chromosome segregation overlap temporally. (edu.pl)