Centromere function requires the proper coordination of several subfunctions, such as kinetochore assembly, sister chromatid cohesion, binding of kinetochore microtubules, orientation of sister kinetochores to opposite spindle poles, and their movement towards the spindle poles. Centromere structure appears to be organized in different, separable domains in order to accomplish these functions. Despite the conserved nature of centromere functions, the molecular genetic definition of the DNA sequences that form a centromere in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, in the fruit fly Drosophila melanogaster, and in humans has revealed little conservation at the level of centromere DNA sequences. Also at the protein level few centromere proteins are conserved in all of these four organisms and many are unique to the different organisms. The recent analysis of the centromere structure in the yeast S. pombe by electron microscopy and detailed immunofluorescence microscopy of ...
The histone protein CenH3 is both necessary and sufficient to trigger the formation of centromeres and pass them on from 1 generation to the next. Centromeres are specialised regions of the genome, which can be identified under the microscope as the primary constriction in X-shaped chromosomes. The cell skeleton, which distributes the chromosomes to the two daughter cells during cell division, attaches to the centromeres. In most organisms the position of the centromere is not determined by the DNA sequence. Scientists from the Max Planck Institute of Immunobiology and Epigenetics in Freiburg have succeeded in demonstrating that the position, function and inheritance of the centromere are determined by the histone CenH3, a DNA packaging protein. This discovery may help to further the development of artificial human chromosomes, which could be used for gene therapies in medicine.. Centromeres provide a platform for the development of a protein complex known as the kinetochore. During cell ...
Our results show for the first time that mouse SGO2 localizes at the inner centromere domain during both meiotic and mitotic divisions, in the same way as its orthologue Sgo2 in fission yeast (Kitajima et al, 2004; Rabitsch et al, 2004). SGO2 and RAD21 colocalize and show a double cornet arrangement at the inner centromere domain below the closely associated sister kinetochores during metaphase I and anaphase I. By contrast, REC8 colocalizes only with the vertical region of the T‐shaped SGO2 signals during these stages (supplementary Fig 4 online). These results show that there are two different cohesin complexes with either RAD21 or REC8 at the inner domain of metaphase I and anaphase I centromeres, and that these complexes coexist only at the vertical region of the T‐shaped SGO2 signals. Thus, SGO2, as has been proposed for Sgo1 in Drosophila and yeast meiosis (Kitajima et al, 2004; Marston et al, 2004; Rabitsch et al, 2004; Clarke et al, 2005), could protect centromeric cohesin ...
Although their role in cell division is essential, centromeres evolve rapidly in animals, plants and yeasts. Unlike the complex centromeres of plants and aminals, the point centromeres of Saccharomcyes yeasts can be readily sequenced to distinguish amongst the possible explanations for fast centromere evolution. Using DNA sequences of all 16 centromeres from 34 strains of Saccharomyces cerevisiae and population genomic data from Saccharomyces paradoxus, I show that centromeres in both species evolve 3 times more rapidly even than selectively unconstrained DNA. Exceptionally high levels of polymorphism seen in multiple yeast populations suggest that rapid centromere evolution does not result from the repeated selective sweeps expected under meiotic drive. I further show that there is little evidence for crossing-over or gene conversion within centromeres, although there is clear evidence for recombination in their immediate vicinity. Finally I show that the mutation spectrum at centromeres is ...
Chapter 11 plant centromere epigenetics 147 ryan n. Questionbank biology unitiii chapter10 cell structure. Those included have been perfected and are now presented for the first time in a usable and teachable form. But it does appear that when a centromere sequence is replicated, the proteins from the original centromere are divided between the two new copies of the centromere dna sequence. Haploid plants produced by centromeremediated genome. Generally similar plants or animals are arranged in particular groups. The nucleosomes of centromeres are characterized by a special h3like histone cenh3, which evolves rapidly and adaptively in drosophila. Centromere of each chromosome lies on the equator and is attached to the spindle fibres. To study centromere dynamics in early meiotic prophase, we performed fluorescence in situ hybridization experiments using centromeric retrotransposon of maize and telomere sequences as probes. Moreover, no haploids were obtained from selffertilized cenh3 mutant ...
The accurate distribution of genetic information to daughter cells during cell division relies on the physical attachment of chromosomes to spindle microtubules mediated by kinetochores. Kinetochores are large protein assemblies deposited at specific chromosomal loci known as centromeres [1], [2], [3]. Defective centromere function results in chromosome segregation errors that can contribute to genomic instability implicated in cancer [4]. Hence, understanding the molecular mechanisms that promote kinetochore establishment and maintenance at centromeres is of prime importance.. The location of most eukaryotic centromeres is determined by the assembly of specialized chromatin composed of nucleosomes in which canonical histone H3 is replaced by the centromere‐specific H3 variant CENP‐A in vertebrates and Cnp1 (CENP‐ACnp1) in Schizosaccharomyces pombe [3], [5]. Thus, the establishment and maintenance of kinetochores requires CENP‐A to be recruited to and deposited at centromeres. In S. ...
Centromere DNA element II (CDEII) of budding yeast centromeres is an AT-rich sequence essential for centromere (CEN) function. Sequence analysis of Saccharomyces cerevisiae CDEIIs revealed that A(5-7)/T(5-7) tracts are statistically overrepresented at the expense of AA/TT and alternating AT. To test the hypothesis that this nonrandom sequence organization is functionally important, a CEN library in which the CDEII sequences were randomized was generated. The library was screened for functional and nonfunctional members following centromere replacement in vivo. Functional CENs contained CDEIIs with the highly biased A(n)/T(n) run distribution of native centromeres, while nonfunctional CDEIIs resembled those picked from the library at random. Run content, defined as the fraction of residues present in runs of four or more nucleotides, of the functional and nonfunctional CDEII populations differed significantly (P | 0.001). Computer searches of the genome for regions with an A + T content comparable to
We have employed a system that utilizes homologous pairs of human DNA-derived yeast artificial chromosomes (YACs) as marker chromosomes to assess the specific role(s) of conserved centromere DNA elements (CDEI, CDEII and CDEIII) in meiotic chromosome disjunction fidelity. Thirteen different centromere (CEN) mutations were tested for their effects on meiotic centromere function. YACs containing a wild-type CEN DNA sequence segregate with high fidelity in meiosis I (99% normal segregation) and in meiosis II (96% normal segregation). YACs containing a 31-bp deletion mutation in centromere DNA element II (CDEII delta 31) in either a heterocentric (mutant/wild type), homocentric (mutant/mutant) or monosomic (mutant/--) YAC pair configuration exhibited high levels (16-28%) of precocious sister-chromatid segregation (PSS) and increased levels (1-6%) of nondisjunction meiosis I (NDI). YACs containing this mutation also exhibit high levels (21%) of meiosis II nondisjunction. Interestingly, significant ...
The HTR12 protein is a centromere-specific histone H3 variant in A. thaliana, and was shown to colocalize with the 180 bp repetitive sequences of all centromeres (Talbert et al., 2002). The Zea mays centromeric histone H3, CENH3 was also detected at the kinetochore regions of the centromere and colocalized with centromere-specific tandem repeat CentC and with centromeric retroelement CRM (Zhong et al., 2002). These results indicate wide conservation of CENP-A-like proteins and their close relationship to the centromeric satellites. In our study, the spatial relationship between HTR12 protein and 180 bp repetitive sequences was investigated by sequential combination of immunolabeling and FISH. In the cell cultures studied here, drastic changes in the copy numbers of 180 bp repetitive sequences had occurred, however, all chromosomes carried the 180 bp repetitive sequences despite their variation in size (Fig. 1E,F). For chromosomes with low numbers of 180 bp repetitive sequences, ...
TY - JOUR. T1 - Involvement of the spliceosomal U4 small nuclear RNA in heterochromatic gene silencing at fission yeast centromeres. AU - Chinen, Madoka. AU - Morita, Misato. AU - Fukumura, Kazuhiro. AU - Tani, Tokio. PY - 2010/2/19. Y1 - 2010/2/19. N2 - prp13-1 is one of the mutants isolated in a screen for defective pre-mRNA splicing at a nonpermissive temperature in fission yeast Schizosaccharomyces pombe. We cloned the prp13+ gene and found that it encodes U4 small nuclear RNA (snRNA) involved in the assembly of the spliceosome. The prp13-1 mutant produced elongated cells, a phenotype similar to cell division cycle mutants, and displays a high incidence of lagging chromosomes on anaphase spindles. The mutant is hypersensitive to the microtubule-destabilizing drug thiabendazole, supporting that prp13-1 has a defect in chromosomal segregation. We found that the prp13-1 mutation resulted in expression of the ura4 + gene inserted in the pericentromeric heterochromatin region and reduced ...
TY - JOUR. T1 - Meiosis-Specific loading of the Centromere-Specific histone CENH3 in Arabidopsis thaliana. AU - Ravi, Maruthachalam. AU - Shibata, Fukashi. AU - Ramahi, Joseph S.. AU - Nagaki, Kiyotaka. AU - Chen, Changbin. AU - Murata, Minoru. AU - Chan, Simon W L. PY - 2011/6. Y1 - 2011/6. N2 - Centromere behavior is specialized in meiosis I, so that sister chromatids of homologous chromosomes are pulled toward the same side of the spindle (through kinetochore mono-orientation) and chromosome number is reduced. Factors required for mono-orientation have been identified in yeast. However, comparatively little is known about how meiotic centromere behavior is specialized in animals and plants that typically have large tandem repeat centromeres. Kinetochores are nucleated by the centromere-specific histone CENH3. Unlike conventional histone H3s, CENH3 is rapidly evolving, particularly in its N-terminal tail domain. Here we describe chimeric variants of CENH3 with alterations in the N-terminal ...
The centromere is a specialized chromosomal region that directs the formation of the kinetochore, a huge protein assembly that acts as the attachment site for spindle microtubules and carries out chromosome movement during cell division. Centromere loss or the presence of extra centromeres adversely affect chromosome segregation and may result in aneuploidy, a condition found in many human tumors and a major cause of miscarriages and birth defects. Consequently, understanding the basis of centromere determination and propagation is of great relevance to both fundamental and clinical research. In recent years, it has become clear that centromeres are defined by the presence of a histone H3 variant known as Centromere Protein A, CENP-A, or CenH3. Much effort has been devoted to understanding the mechanisms that drive the assembly of CENP-A containing nucleosomes exclusively onto centromeric DNA, as well as the peculiar structure of these nucleosomes. We have recently developed an immunofluorescence-based
The kinetochore directs accurate chromosome segregation by controlling chromosome movements through interactions with spindle microtubules, and also by serving as a platform for various regulatory pathways. Kinetochores assemble on centromere chromatin marked by nucleosomes containing the centromere-specific histone H3 variant CENP-A (Allshire and Karpen, 2008; Earnshaw and Rothfield, 1985). The interphase centromere complex (ICEN) associates with the CENP-A nucleosome (Izuta et al., 2006; Obuse et al., 2004), and the constitutive-centromere-associated network (CCAN) forms the inner kinetochore (Basilico et al., 2014; Cheeseman and Desai, 2008; Foltz et al., 2006; Gascoigne et al., 2011; Hori et al., 2008; Okada et al., 2006). The CCAN factors CENP-C (Saitoh et al., 1992) and CENP-T act as a crucial platform for the kinetochore during mitosis (Gascoigne et al., 2011; Hori et al., 2008, 2013; Nishino et al., 2013; Przewloka et al., 2011; Rago et al., 2015). CENP-C binds to CENP-A nucleosomes ...
THE centromeres in most plants and animals contain hundreds of kilobases of simple repeats and interspersed retroelements. Such repetitive domains evolve at remarkable rates-continually expanding, contracting, and generating new arrays (Schueler et al. 2001; Henikoff 2002; Nagaki et al. 2004; Lee et al. 2005; Ma and Bennetzen 2006). This process tends to homogenize centromeres and drive out single- and low-copy sequences that are necessary for sequencing and molecular-marker-based mapping (Henikoff 2002; Dawe 2005). Two relatively simple rice centromeres have been bridged and characterized (Nagaki et al. 2004; Wu et al. 2004; Zhang et al. 2004), but as a rule centromeres fall into large and poorly resolved genetic gaps. In maize, the centromere positions are estimates based on rough interval or trisomic mapping and visual comparisons to the cytogenetic map (Weber and Helentjaris 1989; Schneerman et al. 1998; Lin et al. 2001).. Another complexity of centromere mapping is that sequence alone ...
TY - JOUR. T1 - Precise centromere mapping using a combination of repeat junction markers and chromatin immunoprecipitation-polymerase chain reaction. AU - Luce, Amy C.. AU - Sharma, Anupma. AU - Mollere, Oliver S.B.. AU - Wolfgruber, Thomas K.. AU - Nagaki, Kiyotaka. AU - Jiang, Jiming. AU - Presting, Gernot G.. AU - Dawe, R. Kelly. PY - 2006/11/6. Y1 - 2006/11/6. N2 - Centromeres are difficult to map even in species where genetic resolution is excellent. Here we show that junctions between repeats provide reliable single-copy markers for recombinant inbred mapping within centromeres and pericentromeric heterochromatin. Repeat junction mapping was combined with anti-CENH3-mediated ChIP to provide a definitive map position for maize centromere 8.. AB - Centromeres are difficult to map even in species where genetic resolution is excellent. Here we show that junctions between repeats provide reliable single-copy markers for recombinant inbred mapping within centromeres and pericentromeric ...
Centromeres are unique chromatin domains that direct the site of kinetochore formation during mitosis and mediate the movement of chromosomes during cell division. Centromeres contain a unique nucleosome in which histone H3 is replaced by centromere protein A (CENP-A). Because of their unique position in chromatin, the CENP-A nucleosome was hypothesized to determine the site of centromere and kinetochore assembly. In order to test the long held assumption that CENP-A dictates the location of the centromere; we developed a novel de novo centromere formation assay, which provides a new and powerful constructive approach to studying centromeres. This system is based on a LacO array that is stably integrated into the long arm of chromosome 1, far away from the existing centromere. Targeting the CENP-A chaperone HJURP or the Mis18 complex to the LacO array, by fusing them to the LacI repressor, drove the stable recruitment of CENP-A nucleosomes to the LacO array at the non-centromeric locus. ...
The centromere facilitates the assembly of the kinetochore ensuring the accurate chromosome segregation. Active centromeres are specified epigenetically by nucleosomes containing the histone H3 variant, CENP-A, which is in place of histone H3. CENP-A is deposited by an assembly factor called HJURP in humans and Scm3 in yeast. However, homologs of HJURP/Scm3 are only present in a subset of eukaryotes. How CENP-A is deposited exclusively at centromeres in organisms that lack CENP-A chaperones remains unknown. This thesis addresses the above-mentioned gaps in the understanding of CENP-A assembly and identifies CAL1 as an essential recruiter for Drosophila CENP-A, which fulfills the function of HJURP/Scm3 in the dipteran lineage. Mis-targeting CAL1 is sufficient to trigger the formation of a functional centromere at the ectopic site, where the recruitment of centromeric proteins and microtubule attachments are detected. This additional centromere can be propagated epigenetically to the next generation and
Dicentric chromosomes have been identified as instigators of the genome instability associated with cancer, but this instability is often resolved by one of a number of different secondary events. These include centromere inactivation, inversion, and intercentromeric deletion. Deletion or excision of one of the centromeres may be a significant occurrence in myeloid malignancy and other malignancies but has not previously been widely recognized, and our reports are the first describing centromere deletion in cancer cells. We review what is known about dicentric chromosomes and the mechanisms by which they can undergo stabilization in both constitutional and cancer genomes. The failure to identify centromere deletion in cancer cells until recently can be partly explained by the standard approaches to routine diagnostic cancer genome analysis, which do not identify centromeres in the context of chromosome organization. This hitherto hidden group of primary dicentric, secondary monocentric chromosomes,
Centromeres mediate the conserved and essential process of chromosome segregation, yet centromeric DNA and the centromeric histone, CENP-A, are rapidly evolving. The rapid evolution of loop 1 (L1) of Drosophila CENP-A is thought to modulate the DNA-binding preferences of CENP-A to suppress centromere drive, the preferential transmission of chromosomes with expanded centromeric satellites during female meiosis. Consistent with this model, CENP-A from D. bipectinata (bip) fails to localize to D. melanogaster (mel) centromeres due to amino acid differences between mel and bip L1. Here, I show that this result is, in fact, due to the inability of the mel CENP-A chaperone, CAL1, to incorporate bip CENP-A into chromatin. Co-expression of bip CENP-A and bip CAL1 in mel cells restores centromeric localization, and similar findings apply to other Drosophila species. Furthermore, two co-evolving regions, CENP-A L1 and the CAL1 N-terminus, are identified as critical for lineage-specific CENP-A incorporation.
Large-scale genome rearrangements brought about by chromosome breaks underlie numerous inherited diseases, initiate or promote many cancers and are also associated with karyotype diversification during species evolution. Recent research has shown that these breakpoints are nonrandomly distributed throughout the mammalian genome and many, termed evolutionary breakpoints (EB), are specific genomic locations that are reused during karyotypic evolution. When the phylogenetic trajectory of orthologous chromosome segments is considered, many of these EB are coincident with ancient centromere activity as well as new centromere formation. While EB have been characterized as repeat-rich regions, it has not been determined whether specific sequences have been retained during evolution that would indicate previous centromere activity or a propensity for new centromere formation. Likewise, the conservation of specific sequence motifs or classes at EBs among divergent mammalian taxa has not been determined. To
Centromeres are the differentiated chromosomal domains that specify the mitotic behavior of chromosomes. To examine the molecular basis for the specification of centromeric chromatin, we have cloned a human cDNA that encodes the 17-kD histone-like centromere antigen, CENP-A. Two domains are evident in the 140 aa CENP-A polypeptide: a unique NH2-terminal domain and a 93-amino acid COOH-terminal domain that shares 62% identity with nucleosomal core protein, histone H3. An epitope tagged derivative of CENP-A was faithfully targeted to centromeres when expressed in a variety of animal cells and this targeting activity was shown to reside in the histone-like COOH-terminal domain of CENP-A. These data clearly indicate that the assembly of centromeres is driven, at least in part, by the incorporation of a novel core histone into centromeric chromatin. ...
by Sarah N. Ruckman, Michelle M. Jonika, Claudio Casola, Heath Blackmon. Despite the fundamental role of centromeres two different types are observed across plants and animals. Monocentric chromosomes possess a single region that function as the centromere while in holocentric chromosomes centromere activity is spread across the entire chromosome. Proper segregation may fail in species with monocentric chromosomes after a fusion or fission, which may lead to chromosomes with no centromere or multiple centromeres. In contrast, species with holocentric chromosomes should still be able to safely segregate chromosomes after fusion or fission. This along with the observation of high chromosome number in some holocentric clades has led to the hypothesis that holocentricity leads to higher rates of chromosome number evolution. To test for differences in rates of chromosome number evolution between these systems, we analyzed data from 4,393 species of insects in a phylogenetic framework. We found that ...
Centromeres are the specialized chromosomal sites necessary for poleward movement during mitosis and meiosis in eukaryotes. Commonly, a centromere is evident as a prominent constriction within the heterochromatin of each metaphase chromosome. The attachment to and movement of chromosomes along the spindle is mediated by the proteinaceous kinetochores, which form at the centromeres during cell division.. Despite this highly conserved function, centromeric DNA sequences are not conserved between organisms. For example, human centromeres consist of large blocks (200 kb to several megabases) of tandemly repeated 171-bp α-satellite (Willard, 1998), but the sequences can differ from those of apes on homologous chromosomes (Haaf and Willard, 1997). Similarly, Drosophila melanogaster centromeric regions contain blocks of 5- to 12-bp satellite repeats that do not appear to be shared by homologous centromeres of sibling species (Lohe and Brutlag, 1987).. Plant centromeric regions resemble their mammalian ...
Track indicating the location of the centromere sequences. Centromeres are specialized chromatin structures that are required for cell division. These genomic regions are normally defined by long tracts of tandem repeats, or satellite DNA, that contain a limited number of sequence differences to distinguish the linear order of repeat copies. The size and repetitive nature of these regions mean they are typically not represented in reference assemblies. Unlike all previous versions of the human reference assembly, where the centromere regions have been represented by a multi-megabase gap, GRCh38 incorporates centromere reference models that provide an initial genomic description derived from chromosome-assigned whole genome shotgun (WGS) read libraries of alpha satellite. Each reference model provides an approximation of the true array sequence organization. Although the long-range repeat ordering is not expected to represent the true organization, the submissions are expected to provide a ...
Track indicating the location of the centromere sequences. Centromeres are specialized chromatin structures that are required for cell division. These genomic regions are normally defined by long tracts of tandem repeats, or satellite DNA, that contain a limited number of sequence differences to distinguish the linear order of repeat copies. The size and repetitive nature of these regions mean they are typically not represented in reference assemblies. Unlike all previous versions of the human reference assembly, where the centromere regions have been represented by a multi-megabase gap, GRCh38 incorporates centromere reference models that provide an initial genomic description derived from chromosome-assigned whole genome shotgun (WGS) read libraries of alpha satellite. Each reference model provides an approximation of the true array sequence organization. Although the long-range repeat ordering is not expected to represent the true organization, the submissions are expected to provide a ...
Track indicating the location of the centromere sequences. Centromeres are specialized chromatin structures that are required for cell division. These genomic regions are normally defined by long tracts of tandem repeats, or satellite DNA, that contain a limited number of sequence differences to distinguish the linear order of repeat copies. The size and repetitive nature of these regions mean they are typically not represented in reference assemblies. Unlike all previous versions of the human reference assembly, where the centromere regions have been represented by a multi-megabase gap, GRCh38 incorporates centromere reference models that provide an initial genomic description derived from chromosome-assigned whole genome shotgun (WGS) read libraries of alpha satellite. Each reference model provides an approximation of the true array sequence organization. Although the long-range repeat ordering is not expected to represent the true organization, the submissions are expected to provide a ...
Track indicating the location of the centromere sequences. Centromeres are specialized chromatin structures that are required for cell division. These genomic regions are normally defined by long tracts of tandem repeats, or satellite DNA, that contain a limited number of sequence differences to distinguish the linear order of repeat copies. The size and repetitive nature of these regions mean they are typically not represented in reference assemblies. Unlike all previous versions of the human reference assembly, where the centromere regions have been represented by a multi-megabase gap, GRCh38 incorporates centromere reference models that provide an initial genomic description derived from chromosome-assigned whole genome shotgun (WGS) read libraries of alpha satellite. Each reference model provides an approximation of the true array sequence organization. Although the long-range repeat ordering is not expected to represent the true organization, the submissions are expected to provide a ...
This gene product is a highly conserved protein that facilitates centromere formation. It is a DNA-binding protein that is derived from transposases of the pogo DNA transposon family. It contains a helix-loop-helix DNA binding motif at the N-terminus, and a dimerization domain at the C-terminus. The DNA binding domain recognizes and binds a 17-bp sequence (CENP-B box) in the centromeric alpha satellite DNA. This protein is proposed to play an important role in the assembly of specific centromere structures in interphase nuclei and on mitotic chromosomes. It is also considered a major centromere autoantigen recognized by sera from patients with anti-centromere antibodies. [provided by RefSeq, Jul 2008 ...
Centromeres are the chromosomal regions that link DNA to the spindle during cell division, thus ensuring faithful segregation of genetic material. Proper centromere function is critical for eukaryotic life. Despite the fact that centromeres are essential for life, centromeric architecture is remarkably diverse. Moreover, centromeric DNA sequences and centromeric proteins evolve rapidly in diverse organisms. Despite this, the hallmark of many functional centromeres is the presence of a specialized centromeric H3 variant called CenH3. Despite being essential for chromosome segregation in most eukaryotes, CenH3 also evolves rapidly in plants and animals. I study the rapidly evolution of CenH3 in Drosophila. Specifically, I study instances in which CenH3 has duplicated and may have undergone subfunctionalization. I am intrigued by the possibility that these duplications may have arisen in response to genetic conflict such as centromere drive or due to intralocus antagonism. I use a variety of ...
The centromere-specific histone variant CENP-A (CID in Drosophila) is a structural and functional foundation for kinetochore formation and chromosome segregation. Here, we show that overexpressed CID is mislocalized into normally non-centromeric regions in Drosophila tissue culture cells and animals. Analysis of mitoses in living and fixed cells reveals that mitotic delays, anaphase bridges, chromosome fragmentation, and cell and organismal lethality are all direct consequences of CID mislocalization. In addition, proteins that are normally restricted to endogenous kinetochores assemble at a subset of ectopic CID incorporation regions. The presence of microtubule motors and binding proteins, spindle attachments, and aberrant chromosome morphologies demonstrate that these ectopic kinetochores are functional. We conclude that CID mislocalization promotes formation of ectopic centromeres and multicentric chromosomes, which causes chromosome missegregation, aneuploidy, and growth defects. Thus, CENP-A
In most eukaryotes, centromeres are epigenetically defined by nucleosomes that contain the histone H3 variant centromere protein A (CENP-A). Specific targeting of the CENP-A-loading chaperone to the centromere is vital for stable centromere propagation; however, the existence of ectopic centromeres …
The centromere is together with telomeres and origin of replications one of the essential parts of any eukaryotic chromosomes. The centromere is usually defined by specific DNA sequences which are in higher eukaryotes typical tandem repetitive sequences, often called satellite DNA. These sequences bind specific proteins called cen-Proteins. During mitosis the centromeres can be identified in particular during the metaphase stage as a constriction at the chromosome. At this centromeric constriction the two mostly identical halves of the chromosome, the sister chromatids, are held together until late metaphase. During mitotic division, a transient structure called kinetochore is formed on top of the centromeres. The kinetochores are the sites where the spindle fibers attach. Kinetochores and the spindle apparatus are responsible for the movement of the two sister chromatids to opposite poles of dividing cell nucleus during anaphase. Usually the mitosis is immediately followed by a cell ...
DNA methylation is an epigenetically imposed mark of transcriptional repression that is essential for maintenance of chromatin structure and genomic stability. Genome-wide methylation patterns are mediated by the combined action of three DNA methyltransferases: DNMT1, DNMT3A and DNMT3B. Compelling links exist between DNMT3B and chromosome stability as emphasized by the mitotic defects that are a hallmark of ICF syndrome, a disease arising from germline mutations in DNMT3B. Centromeric and pericentromeric regions are essential for chromosome condensation and the fidelity of segregation. Centromere regions contain distinct epigenetic marks, including dense DNA hypermethylation, yet the mechanisms by which DNA methylation is targeted to these regions remains largely unknown. In the present study, we used a yeast two-hybrid screen and identified a novel interaction between DNMT3B and constitutive centromere protein CENP-C. CENP-C is itself essential for mitosis. We confirm this interaction in ...
Mitotic sister chromosomes individually attach to and harness the power of dynamic MT ends while maintaining an intercentromere elastic linkage that enables them to translocate jointly on the mitotic spindle and orient facing opposite spindle poles (Shelby et al., 1996). Robust MT attachments and proper orientation facing the opposite spindle poles maximizes the elastic pull on the sister centromeres and signals the cell that anaphase may safely commence. We have found that ectopically increasing the level of MCAK activity on centromeres decreases sister centromere tension, although not to the point that the spindle checkpoint is triggered. Conversely, decreased levels of MCAK on centromeres substantially increased tension across sister centromeres. Our data contradicts two other studies that suggest that the depletion of MCAK has no effect on tension (Ganem et al., 2005) or decreases tension (Kline-Smith et al., 2004). We believe that this discrepancy may be caused by the inclusion of ...
Our lab is interested in the epigenetic inheritance and organization of centromeres. The DNA sequence independent transmission of centromere identity through many cell generations is highly relevant for proper genome regulation and when perturbed can lead to genome instability and cellular malfunction. We use the fruit fly Drosophila melanogaster and human cells as a model organism to address the following questions: How is the epigenetic identity of centromeres regulated?. Centromeres are found at the primary constriction of chromosomes in mitosis where they remain connected before cell division. This structure is essential for an equivalent chromosomes distribution to the daughter cells. The centromere specific histone H3-variant CENP-AcenH3 is essential for kinetochore formation and centromere function. We have previously established a biosynthetic approach to target dCENP-AcenH3 to specific non-centromeric sequences such as the Lac Operator and follow the formation of functional ...
Stringent regulation of cellular levels of evolutionarily conserved centromeric histone H3 variant (CENP-A in humans, CID in flies, Cse4 in yeast) prevents its mislocalization to non-centromeric chromatin. Overexpression and mislocalization of CENP-A has been observed in cancers and leads to aneuploidy in yeast, flies, and human cells. Ubiquitin-mediated proteolysis of Cse4 by E3 ligases such as Psh1 and Sumo-Targeted Ubiquitin Ligase (STUbL) Slx5 prevent mislocalization of Cse4. Previously, we identified Siz1 and Siz2 as the major E3 ligases for sumoylation of Cse4. In this study, we have identified lysine 65 (K65) in Cse4 as a site that regulates sumoylation and ubiquitin-mediated proteolysis of Cse4 by Slx5. Strains expressing cse4 K65R exhibit reduced levels of sumoylated and ubiquitinated Cse4 in vivo. Furthermore, co-immunoprecipitation experiments reveal reduced interaction of cse4 K65R with Slx5, leading to increased stability and mislocalization of cse4 K65R under normal physiological ...
Histone acetylation may act to mark and maintain transcriptionally active or inactive chromosomal domains through the cell cycle and in different lineages. A novel role for histone acetylation in centromere regulation has been identified. Exposure of fission yeast cells to TSA, a specific inhibitor …
KAT7/HBO1/MYST2 Regulates CENP-A Chromatin Assembly by Antagonizing Suv39h1-Mediated Centromere InactivationKAT7/HBO1/MYST2 Regulates CENP-A Chromatin Assembly by Antagonizing Suv39h1-Mediated Centromere Inactivation ...
Author Summary The centromere is a chromosome domain essential for the correct partitioning of chromosomes during mitotic and meiotic cell divisions. The characterization of the centromeric proteins and their sequential assembly have been extensively studied in mammalian mitosis, since defective chromosome segregation is associated with birth defects and cancer. However, few studies have analyzed the centromere assembly during meiosis, a special cell division leading to the production of haploid gametes. Here, we analyze the sequence of loading of several centromeric and kinetochoric proteins during male mouse meiosis. We show that during both meiotic divisions, the proteins of the chromosomal passenger complex Borealin, INCENP, and Aurora-B load sequentially to the inner centromere before Shugoshin 2 and MCAK. The outer kinetochore proteins BubR1 and CENP-E are the last ones to be assembled. We also demonstrate, using a knockout mouse for Sgol2, that the inner centromeric protein Shugoshin 2 is
Inner centromere protein is a protein that in humans is encoded by the INCENP gene.[5][6][7] In mammalian cells, two broad groups of centromere-interacting proteins have been described: constitutively binding centromere proteins and passenger (or transiently interacting) proteins.[8] The constitutive proteins include CENPA (centromere protein A), CENPB, CENPC1, and CENPD. The term passenger proteins encompasses a broad collection of proteins that localize to the centromere during specific stages of the cell cycle.[9] These include CENPE; MCAK; KID; cytoplasmic dynein (e.g., DYNC1H1); CliPs (e.g. CLIP1); and CENPF/mitosin (CENPF). The inner centromere proteins (INCENPs),[5] the initial members of the passenger protein group, display a broad localization along chromosomes in the early stages of mitosis but gradually become concentrated at centromeres as the cell cycle progresses into mid-metaphase. During telophase, the proteins are located within the midbody in the intercellular bridge, where ...
This organism was chosen because it has epigenetically defined regional centromeres whose chromatin and protein compositions are similar to those of their human counterparts, to identify factors responsible for the replacement of histone H3 with CENP-A at centromeres.. In this report, the KAIST research group systematically analyzed the roles of the ATP-dependent chromatin-remodelers in the centromeric chromatin assembly of fission yeast as they serve as strong candidates for such factors ...
Centromeres are essential for cell division and growth in all eukaryotes, and knowledge of their sequence and structure guides the development of artificial chromosomes for functional cellular biology studies. Centromeric proteins are conserved among eukaryotes; however, centromeric DNA sequences are highly variable. We combined forward and reverse genetic approaches with chromatin immunoprecipitation to id
Centromeres are specialized chromosomal domains which are composed of centromeric DNA, often enriched in satellite repeats, and a large protein complex, the kinetochore. Proper assembly of the kinetochore complex is a prerequisite for the correct segregation of chromosomes during mitotic and meiotic divisions and, consequently, for genome stability in all eukaryotic organisms. Deposition of the centromeric histone H3 variant CenH3 at the centromeric region is a prerequisite for correct assembly and function of the kinetochore complex in most eukaryotes. CenH3 deposition depends on cenH3 assembly factors, like KNL2 (Lermontova et al., 2013; Sandmann et al., 2017), chaperones (e.g. NASPSIM3, Le Goff et al., 2020), transcription of the centromeric repeats and the epigenetic status of centromeric chromatin. Specific manipulation of the CenH3 assembly factor KNL2 yielded double haploids in Arabidopsis thaliana (I. Lermontova, WO2017/067714). The production of double haploids enables a shortcut to ...
CP1 is a yeast protein which binds to the highly conserved DNA element I (CDEI) of yeast centromeres. We have purified CP1 to near homogeneity; it is comprised of a single polypeptide of molecular weight 58,400. When bound to yeast CEN3 DNA, CP1 protects a 12-15-base pair region centered over CDEI. Methylation interference experiments show that methylations of residues located outside of the 8-base pair CDEI sequence have no detectable effect on CP1 binding, suggesting that the DNA sequences important for CP1 recognition are confined to the CDEI octanucleotide. The equilibrium constant for CP1 binding to CEN3 DNA is relatively low, 3 x 10(8) M-1. Using a novel method to determine relative DNA binding constants, we analyzed the effect of CDEI mutations on CP1 binding. A C to T point mutation at position 5 (CO1) reduces the equilibrium constant about 35-fold, while the insertion of an additional T at this position (CAT) reduces the equilibrium constant 1,400-fold. The effect of these mutations on mitotic
As the spindle fiber attachment region of the chromosome, the centromere has been investigated in a variety of contexts. Here, we will review current knowledge about this unique chromosomal region and its relevance for proper cell division, speciation, and disease. Understanding the three-dimensional organization of centromeres in normal and turner cells is just beginning to emerge. Multidisciplinary research will allow for new insights into its normal and aberrant nuclear organization and may allow for new therapeutic interventions that target events linked to centromere function and cell division ...
BACKGROUND: Survivin is a mammalian protein that carries a motif typical of the inhibitor of apoptosis (IAP)proteins, first identified in baculoviruses. Although baculoviral IAP proteins regulate cell death, the yeast Survivin homolog Bir1 is involved in cell division. To determine the function of Survivin in mammals, we analyzed the pattern of localization of Survivin protein during the cell cycle, and deleted its gene by homologous recombination in mice. RESULTS: In human cells, Survivin appeared first on centromeres bound to a novel para-polar axis during prophase/metaphase, relocated to the spindle midzone during anaphase/telophase, and disappeared at the end of telophase. In the mouse, Survivin was required for mitosis during development. Null embryos showed disrupted microtubule formation, became polyploid, and failed to survive beyond 4.5days post coitum. This phenotype, and the cell-cycle localization of Survivin, resembled closely those of INCENP. Because the yeast homolog of INCENP, Sli15,
Following a close collaboration with the Chan lab and the demise of Simon Chan in the Summer of 2012, we have assimilated Chan lab researchers working on different aspects of centromeric function and its epigenetic determination. We are investigating the structural features, evolutionary constraints, and mechanisms that determine the interaction of centromeric histone H3 (CENH3) with the centromere and its instability in outcrosses resulting in parent-specific genome elimination. We are investigating the mechanisms of extreme chromosome fragmentation and reassembly that are associated to chromosome elimination. ...
We report the interaction between a human centromere antigen and an alphoid DNA, a human centromeric satellite DNA, which consists of 170-bp repeating units. A cloned alphoid DNA fragment incubated with a HeLa cell nuclear extract is selectively immunoprecipitated by the anticentromere sera from scleroderma patients. Immunoprecipitation of the DNA made by primer extension defines the 17-bp segment on the alphoid DNA that is required for formation of DNA-antigen complex. On the other hand, when proteins bound to the biotinylated alphoid DNA carrying the 17-bp motif are recovered by streptavidin agarose and immunoblotted, the 80-kD centromere antigen (CENP-B) is detected. DNA binding experiments for proteins immunoprecipitated with anticentromere serum, separated by gel electrophoresis, and transferred to a membrane strongly suggest that the 80-kD antigen specifically binds to the DNA fragment with the 17-bp motif. The 17-bp motif is termed the CENP-B box. Alphoid monomers with the CENP-B box ...
TY - JOUR. T1 - Mitotic centromere-associated kinesin is a novel marker for prognosis and lymph node metastasis in colorectal cancer. AU - Ishikawa, K.. AU - Kamohara, Y.. AU - Tanaka, F.. AU - Haraguchi, N.. AU - Mimori, K.. AU - Inoue, H.. AU - Mori, M.. N1 - Funding Information: We thank Dr Y Nakamura, Ms T Shimooka, Ms K Ogata, Ms M Kasagi and Ms Y Nakagawa for their technical assistance and advice. This work was supported in part by the following grants and foundations: CREST, Japan Science and Technology Agency; Japan Society for the Promotion of Science Grant-in-Aid for Scientific Research, grants 17109013, 17591411, 17591413, 18390367, 18590333, 18659384, 18790964, 19890336 and 19591509; The Ministry of Education, Culture, Sports, Science and Technology Grant-in-Aid for Scientific Research on Priority Areas, Grant 18015039; Third Term Comprehensive Ten-Year Strategy for Cancer Control, Grant 16271201.. PY - 2008/6/3. Y1 - 2008/6/3. N2 - Mitotic centromere-associated kinesin (MCAK) is a ...
The organization, evolution and function of eukaryotic centromeres represent a deficiency in our understanding of genome biology. The discovery of human clinical neocentromeres and ENCs has further complicated, on one hand, our understanding of the centromere. On the other hand, neocentromeres and ENCs have allowed an initial dissection of centromere complexity. They have made evident, for instance, its epigenetic nature. The ENC analysis we have accomplished in the present study has contributed to the identification of factors that, very likely, play a crucial role in ENC progression and fixation in the population. We have provided strong evidence that the pericentromeric duplication activity is an intrinsic property of ENCs. This conclusion was mainly supported by FISH experiments using species-specific BAC clones that detected SDs around the centromere in almost all studied ENCs. A deep restructuring was particularly evident in MMU17 (human 13) and MMU2 (human 3). The latter ENC showed a ...
Chicken (Gallus gallus domesticus, GGA) and Japanese quail (Coturnix coturnix japonica, CCO) karyotypes are very similar. They have identical chromosome number (2n = 78) and show a high degree of synt
We describe a process in meiotic cells of budding yeast in which chromosomes become joined together in pairs at their centromeres independent of chromosomal homology. These centromeric interactions depend on the synaptonemal complex component Zip1. During meiosis in wild-type diploids, centromere couples are initially nonhomologous and then undergo switching until all couples involve homologs. This transition to homologous coupling depends on Spo11, a protein required for the initiation of meiotic recombination. Regions of synaptonemal complex assembled early in meiosis are often centromere-associated. We propose that centromere coupling facilitates homolog pairing and promotes synapsis initiation. ...
P>We conducted genome-wide mapping of cytosine methylation using methylcytosine immunoprecipitation combined with Illumina sequencing. The chromosomal distribution pattern of methylated DNA is similar to the heterochromatin distribution pattern on rice chromosomes. The DNA methylation patterns of rice genes are similar to those in Arabidopsis thaliana, including distinct methylation patterns asssociated with gene bodies and promoters. The DNA sequences in the core domains of rice Cen4, Cen5 and Cen8 showed elevated methylation levels compared with sequences in the pericentromeric regions. In addition, elevated methylation levels were associated with the DNA sequences in the CENH3-binding subdomains, compared with the sequences in the flanking H3 subdomains. In contrast, the centromeric domain of Cen11, which is composed exclusively of centromeric satellite DNA, is hypomethylated compared with the pericentromeric domains. Thus, the DNA sequences associated with functional centromeres can be ...
Constitutive heterochromatin, mainly formed at the gene-poor regions of pericentromeres, is believed to ensure a condensed and transcriptionally inert chromatin conformation. Pericentromeres consist of repetitive tandem satellite repeats and are crucial chromosomal elements that are responsible for accurate chromosome segregation in mitosis. The repeat sequences are not conserved and can greatly vary between different organisms, suggesting that pericentromeric functions might be controlled epigenetically. In this review, we will discuss how constitutive heterochromatin is formed and maintained at pericentromeres in order to ensure their integrity. We will describe the biogenesis and the function of main epigenetic pathways that are involved and how they are interconnected. Interestingly, recent findings suggest that alternative pathways could substitute for well-established pathways when disrupted, suggesting that constitutive heterochromatin harbors much more plasticity than previously assumed. In
The essential histone H3 variant Cse4 plays a crucial role at the centromere in S. cerevisiae, where it replaces histone H3 in that it assembles centromere specific (Cse4-H4)2 tetrameres. We found in our study that the histone H3 variant was able to interact over its unique N-Terminus with two subunits of the histone acetyltransferase complex SAS-I: Sas2 and Sas4. Mutations within the acetyl-CoA binding site (HAT domain) or the zink-finger of Sas2 disrupted the binding to Cse4, although an indirect interaction was found with co-immunoprecipitation experiments. Additionally, the N-terminus of Cse4 interacted with Cac1, the largest subunit of the chromatin assembly factor CAF-I and Asf1 - two histone chaperones that assemble histones H3 and H4 into nucleosomes. Our findings further suggest a role of Cac1 independent of Cac2 and Cac3 as no binding to Cse4 could be detected. A role for Sas2 at the centromere was further confirmed in that a sas2 deletion (sas2 delta) disrupted the binding of Cse4 to ...
TY - JOUR. T1 - UA62784, a novel inhibitor of centromere protein E kinesin-like protein. AU - Henderson, Meredith C.. AU - Shaw, Yeng Jeng Y.. AU - Wang, Hong. AU - Han, Haiyong. AU - Hurley, Laurence H.. AU - Flynn, Gary. AU - Dorr, Robert T.. AU - Von Hoff, Daniel D.. PY - 2009/1/1. Y1 - 2009/1/1. N2 - Pancreatic carcinoma is the fourth leading cause of death from cancer. Novel targets and therapeutic options are needed to aid in the treatment of pancreatic cancer. The compound UA62784 is a novel fluorenone with inhibitory activity against the centromere protein E (CENP-E) kinesin-like protein. UA62784 was isolated due to its selectivity in isogenic pancreatic carcinoma cell lines with a deletion of the DPC4 gene. UA62784 causes mitotic arrest by inhibiting chromosome congression at the metaphase plate likely through inhibition of the microtubule-associated ATPase activity of CENP-E. Furthermore, CENP-E binding to kinetochores duringmitosis is not affected by UA62784, suggesting that the ...
Model for heterochromatin assembly and spreading at S. pombecentromeric outer repeats. Heterochromatic centromere sequences (yellow arrow) are transcribed by RNA Polymerase II. These centromere transcripts are targeted by RITS via siRNA loaded Ago1. Association of RITS with centromere heterochromatin is strengthened by binding of Chp1 to H3mK9. RITS activity can recruit both CLRC, via interactions with Stc1, and RDRC resulting in spreading of H3mK9 and amplification of siRNAs, respectively (see text for details). dsRNA generated either by bi-directional transcription from centromere promoters (black arrows) or by RDRC activity is recognized and processed by Dicer (Dcr1). The resulting centromere siRNAs are then loaded onto Ago1 first in the ARC complex and then in RITS ...
Kelly Dawe. Distinguished Research Professor What are plant centromeres made of? How are they inherited, what proteins interact with them, and how do they evolve? What are centromeres? For over twelve years our lab has been working through the answers to these questions.lab was founded with the goal of understanding plant kinetochores. We have made good progress mostly by making specific antisera and combining the power of maize cytogenetics with 3D light microscopy. Much of our effort has focused on the inner kinetochore proteins Centromeric Histone H3 (CENH3) and Centromere Protein C (CENP-C), as well as MAD2, a spindle checkpoint protein that localizes to the outer kinetochore. We have worked on a serine-50 phosphorylated form of CENH3, NDC80, and several other kinetochore proteins. Our long-term goal is to identify the complete collection of inner kinetochore proteins, and to develop a model for how these proteins are organized. We intend to pursue the tried-and-true method of identifying ...
TY - JOUR. T1 - Phosphorylation-enabled binding of SGO1-PP2A to cohesin protects sororin and centromeric cohesion during mitosis. AU - Liu, Hong. AU - Rankin, Susannah. AU - Yu, Hongtao. PY - 2013/1. Y1 - 2013/1. N2 - Timely dissolution of sister-chromatid cohesion in mitosis ensures accurate chromosome segregation to guard against aneuploidy and tumorigenesis. The complex of shugoshin and protein phosphatase 2A (SGO1-PP2A) protects cohesin at centromeres from premature removal by mitotic kinases and WAPL in prophase. Here we address the regulation and mechanism of human SGO1 in centromeric cohesion protection, and show that cyclin-dependent kinase (CDK)-mediated, mitosis-specific phosphorylation of SGO1 activates its cohesion-protection function and enables its direct binding to cohesin. The phospho-SGO1-bound cohesin complex contains PP2A, PDS5 and hypophosphorylated sororin, but lacks WAPL. Expression of non-phosphorylatable sororin bypasses the requirement for SGO1-PP2A in centromeric ...
Product Monkey Centromere protein R(ITGB3BP) ELISA kit From B-Gene - A sandwich ELISA for quantitative measurement of Monkey Centromere protein R(ITGB3BP) in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species. Kit contents: 1. MICROTITER PLATE * 1 2. ENZYME CONJUGATE*1 vial 3. STANDARD A*1 vial 4. STANDARD B*1 vial 5. STANDARD C*1 vial 6. STANDARD D*1 vial 7. STANDARD E*1 vial 8. STANDARD F*1 vial 9. SUBSTRATE A*1 vial 10. SUBSTRATE B*1 vial 11. STOP SOLUTION*1 vial 12. WASH SOLUTION (100 x)*1 vial 13. BALANCE SOLUTION*1 vial 14. INSTRUCTION*1
The centromere is a special region of a chromosome, usually near the middle. It is where the two identical sister chromatids stay in contact as the chromosome attaches to the spindle in mitosis. The region contains specific types of DNA, which are tandem repetitive sequences (satellite DNA). These sequences bind specific proteins called cen-proteins. During mitosis the centromeres can be seen during the metaphase stage as a constriction at the chromosome. At this centromeric constriction the two halves of the chromosome, the sister chromatids, are held together until late metaphase. ...
The centromere is a special region of a chromosome, usually near the middle. It is where the two identical sister chromatids stay in contact as the chromosome attaches to the spindle in mitosis. The region contains specific types of DNA, which are tandem repetitive sequences (satellite DNA). These sequences bind specific proteins called cen-proteins. During mitosis the centromeres can be seen during the metaphase stage as a constriction at the chromosome. At this centromeric constriction the two halves of the chromosome, the sister chromatids, are held together until late metaphase. ...
Two ZMPSTE24 mutations in the yeast to complement the (S. cerevisiae) mating defect STE24 and Ras-converting enzyme 1 (RCE1; another prenylprotein-specific endoprotease) genes [§§] (farnesylated protein-converting enzymes 1 and 2) is a significant component of the rice centromere antigens lamin A/C and B1 identified (in non-transgenic plants that go awry↩ (centromere) in cancer), the Ras…
Centromeres are the differentiated chromosomal domains that specify the mitotic behavior of chromosomes. CENPA encodes a centromere protein which contains a histone H3 related histone fold domain that is required for targeting to the centromere. Centromere protein A is proposed to be a component of a modified nucleosome or nucleosome-like structure in which it replaces 1 or both copies of conventional histone H3 in the (H3-H4)2 tetrameric core of the nucleosome particle. The protein is a replication-independent histone that is a member of the histone H3 family. Alternative splicing results in multiple transcript variants encoding distinct isoforms.
Users of the eukaryotic phylum Apicomplexa are the cause of important human being diseases including malaria toxoplasmosis and cryptosporidiosis. transgenic parasite lines expressing epitope-tagged centromeric H3 variant CenH3 we determine the centromeres of chromosomes by hybridization of chromatin immunoprecipitations to genome-wide microarrays (ChIP-chip). We demonstrate that centromere attachment to the centrocone persists throughout the parasite cell cycle and that centromeres localize to a single apical region within the nucleus. Centromere sequestration provides a mechanism for Meloxicam (Mobic) the organization of the nucleus and the maintenance of genome integrity. tachyzoites featuring the simplest form endodyogeny bud into two daughters after each round of DNA replication (3). the causative agent of malaria divides by schizogony whereby the cell proceeds through several rounds of DNA replication and mitosis before the right now multinucleate schizont gives rise to multiple zoites at ...
Cnp1, Mis6, and Mis13 are required for localizing condensin at the kinetochore. (A) Cells cultured at 26°C in EMM2 were observed for the colocalization of Cnd1-GFP with Mis12-RFP, a centromere/kinetochore protein. The numbers in the right panels indicate time in minutes. The enlarged images of Cnd1-GFP (left), Mis12-RFP (middle), and the merged images (right) at 13 min are shown in the insets. (B) Cut14-GFP and Sad1-RFP were observed in the wild-type, mis6-302, cnp1-1, mis13-1, mis16-53, and mis18-262 mutants cultured at 26°C and were shifted to 36°C for 8 h. (C) Chromosomally integrated Cnp1/CENP-A-GFP expressed under the native promoter was observed in the wild-type and cut14-208 mutant cultured at 36°C for 2 h. (D) A ChIP assay was performed using extracts of block-released nda3-311 mutant that expressed Cut14-Flag. The probes were from the central centromere, cnt1 (c10, c9, and c7.5), imr1 (c4 and c1), the outer centromere dg, and the noncentromeric lys1+. WCE, whole cell extract; IP, ...
Saffery, Richard, Sumer, Huseyin, Hassan, Sara, Wong, Lee H, Craig, Jeffrey M, Todokoro, Kazuo, Anderson, Melissa, Stafford, Angela and Choo, KH Andy 2003, Transcription within a functional human centromere, Molecular cell, vol. 12, no. 2, pp. 509-516, doi: 10.1016/S1097-2765(03)00279-X. ...
Sigma-Aldrich offers abstracts and full-text articles by [Mourad Sanhaji, Andreas Ritter, Hannah R Belsham, Claire T Friel, Susanne Roth, Frank Louwen, Juping Yuan].
A DNA-binding protein that interacts with a 17-base pair sequence known as the CENP-B box motif. The protein is localized constitutively to the CENTROMERE and plays an important role in its maintenance ...
A clue about what role this structure, called the PIN domain, might play in heterochromatin assembly came from scouring a protein database. The team found that other proteins that had similar structural features were associated with telomeres, the cap-like structures at the end of chromosomes. In fission yeast, telomeres are one of the locations where heterochromatin is found, another being the centromere -- the dense knob-like structure at the center of a chromosome. The team found that deleting the PIN domain from Chp1 prevented heterochromatin formation at the telomeres but didnt affect formation at the centromere. This suggests different functions of RITS proteins at centromeres vs telomeres, says Joshua-Tor. RITS might be exerting its effect at centromeres through Ago1 and the RNAi machinery, but might enforcing its function at the telomeres through Chp1 and its PIN domain. The team is now turning its focus to understanding how these various functions are regulated.. The Chp1-Tas3 ...
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TY - GEN. T1 - Distribution of centromeric proteins and PARP-1 during mitosis and apoptosis. AU - Perdoni, Federica. AU - Bottone, Maria Grazia. AU - Soldani, Cristiana. AU - Veneroni, Paola. AU - Alpini, Claudia. AU - Pellicciari, Carlo. AU - Scovassi, Anna Ivana. PY - 2009/8. Y1 - 2009/8. N2 - A large complex of proteins, called CENPs, are associated with centromeric DNA. Some of them exhibit a cell cycle-related expression (e.g., CENP-E and -F) and are required for the transition from interphase to mitosis, whereas constitutive proteins (e.g., CENP-A, -B, -C, -G, and -H) reside permanently at the centromere and are essential for the correct kinetochore assembly. Poly(ADP-ribose) polymerase-1 (PARP-1), which plays an active role in many basic processes, was described as a possible regulator of CENPs. By multicolor immunofluorescence we therefore analyzed the distribution of PARP-1 and its interaction with CENP-B, -E, and -F during mitosis and apoptosis.. AB - A large complex of proteins, ...
The human centromere protein B (CENP-B), one of the centromere components, specifically binds a 17 bp sequence (the CENP-B box), which appears in every other alpha-satellite repeat. In the present study, the crystal structure of the complex of the DNA-binding region (129 residues) of CENP-B and the CENP-B box DNA has been determined at 2.5 A resolution. The DNA-binding region forms two helix-turn-helix domains, which are bound to adjacent major grooves of the DNA. The DNA is kinked at the two recognition helix contact sites, and the DNA region between the kinks is straight. Among the major groove protein-bound DNAs, this kink-straight-kink bend contrasts with ordinary round bends (gradual bending between two protein contact sites). The larger kink (43 degrees ) is induced by a novel mechanism, phosphate bridging by an arginine-rich helix: the recognition helix with an arginine cluster is inserted perpendicularly into the major groove and bridges the groove through direct interactions with ...
ATRX is a member of the SNF2 family of helicase/ATPases that is thought to regulate gene expression via an effect on chromatin structure and/or function. Mutations in the hATRX gene cause severe syndromal mental retardation associated with alpha-thalassemia. Using indirect immunofluorescence and confocal microscopy we have shown that ATRX protein is associated with pericentromeric heterochromatin during interphase and mitosis. By coimmunofluorescence, ATRX localizes with a mouse homologue of the Drosophila heterochromatic protein HP1 in vivo, consistent with a previous two-hybrid screen identifying this interaction. From the analysis of a trap assay for nuclear proteins, we have shown that the localization of ATRX to heterochromatin is encoded by its N-terminal region, which contains a conserved plant homeodomain-like finger and a coiled-coil domain. In addition to its association with heterochromatin, at metaphase ATRX clearly binds to the short arms of human acrocentric chromosomes, where the arrays
Structure, Function, Composition and Regulation of the Yeast Kinetochore and Mitotic Spindle. The mitotic spindle is a complex structure that must undergo a highly coordinated sequence of steps to faithfully segregate chromosomes to daughter cells. In each cell cycle the spindle must assemble, form a bipolar connection to each chromosome, segregate one copy of each chromosome to each daughter cell, and then disassemble. Using a combination of proteomics, biochemistry and genetics, we have identified many novel kinetochore and spindle proteins and sub-complexes. A particular emphasis of our work is on the kinetochore, a protein complex that joins chromosomal DNA to mitotic spindle microtubules. Although the budding yeast cell has a simple centromeric DNA sequence, the kinetochore that is assembled onto this sequence contains over 40 proteins. We would like to understand why this structure needs to contain so many subunits, how its assembly is regulated during the cell cycle, how it can associate ...
Eukaryotic centromeres and telomeres are specialized chromosomal regions that share one common characteristic: their underlying DNA sequences are assembled into heritably repressed chromatin. Silent chromatin in budding and fission yeast is composed of fundamentally divergent proteins tat assemble very different chromatin structures. However, the ultimate behaviour of silent chromatin and the pathways that assemble it seem strikingly similar among Saccharomyces cerevisiae (S. cerevisiae), Schizosaccharomyces pombe (S. pombe) and other eukaryotes. Thus, studies in both yeasts have been instrumental in dissecting the mechanisms that establish and maintain silent chromatin in eukaryotes, contributing substantially to our understanding of epigenetic processes. In this review, we discuss current models for the generation of heterochromatic domains at centromeres and telomeres in the two yeast species.. ...
The position of a mouse DNA repeat located near the centromere of mouse chromosomes X, 11, 13, and 17 was examined in interphase nuclei of bone marrow and fibroblast cells by in situ hybridization of 3H- or biotin-labeled DNA probe 70-38. In most laboratory mouse strains this probe recognizes a single repeat cluster (DXWas70) close to the centromere of the mouse X chromosome. In a few mouse strains, a second locus (D11Was70, D13Was70, or D17Was70, depending on the mouse strain) is located near the centromere of an autosome. In interphase nuclei from mouse strains with the X-linked locus only, two distinct sites of hybridization were found in female mice and one in male mice. These two sites remained separated during the different phases of the cell cycle (G1, early S, late S, and G2) as demonstrated by in situ hybridization of the probe to flow-sorted nuclei. In interphase nuclei from mouse strains with both the X-linked locus and an autosomal locus, four distinct sites of hybridization were found in
Read Online or Download Centromeres And Kinetochores: Discovering The Molecular Mechanisms Underlying Chromosome Inheritance (progress In Molecular And Subcellular Biology) by Many In PDF. More Science Books on My TxT!
Given an estimated length of 20.1µm for chromosome 1Q and the mean percentage above, this BAC is approximately 15.6µm±0.4µm from the chromosome centromere. ...
Given an estimated length of 20.1µm for chromosome 1Q and the mean percentage above, this BAC is approximately 15.6µm±0.4µm from the chromosome centromere. ...
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We used synthetic biology approaches to design and build an artificial human chromosome whose centromere chromatin can be modified as desired by targeting chimeric protein tools. This was done in an a ongoing collaboration with Vladimir Larionov at the NIH in the USA and Hiroshi Masumoto at the Kazusa DNA Institute in Japan. Our recent studies with this system have focused on analysis of the role of transcription and open chromatin in kinetochore function. This system offers unique opportunities both for functional analysis of kinetochore epigenetics, but also for gene therapy.. ...