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Pcs1 and Mde4 are inner centromere proteins required to prevent merotelic kinetochore orientation

ABSTRACT: Chromosome segregation depends on proper attachment of sister kinetochores to microtubules. Merotelic kinetochore orientation is an error which occurs when a single kinetochore is attached to microtubules emanating form opposite poles. Mechanisms preventing or correcting the merotelic attachment must operate to avoid chromosome missegregation. Pcs1 has been implicated in preventing merotelic attachment in mitosis and meiosis II. We describe here the identification of Mde4 protein which forms a complex with the Pcs1. Both Mde4 and Pcs1 localize to the central core of the centromere. Similarly to the pcs1 mutant, in the absence of mde4 lagging chromosomes are frequently observed during mitosis and meiosis II . We provide the first evidence that the lagging chromosomes in pcs1 and mde4 mutants are due to merotelic kinetochore orientation. Keywords: ChIP-chip analysis

ORGANISM(S): Schizosaccharomyces pombe

PROVIDER: GSE5257 | GEO | 2007/06/18

SECONDARY ACCESSION(S): PRJNA96477

REPOSITORIES: GEO

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Pcs1 and Mde4 are inner centromere proteins required to prevent merotelic kinetochore orientation

Project description:Chromosome segregation depends on proper attachment of sister kinetochores to microtubules. Merotelic kinetochore orientation is an error which occurs when a single kinetochore is attached to microtubules emanating form opposite poles. Mechanisms preventing or correcting the merotelic attachment must operate to avoid chromosome missegregation. Pcs1 has been implicated in preventing merotelic attachment in mitosis and meiosis II. We describe here the identification of Mde4 protein which forms a complex with the Pcs1. Both Mde4 and Pcs1 localize to the central core of the centromere. Similarly to the pcs1 mutant, in the absence of mde4 lagging chromosomes are frequently observed during mitosis and meiosis II . We provide the first evidence that the lagging chromosomes in pcs1 and mde4 mutants are due to merotelic kinetochore orientation. Keywords: ChIP-chip analysis ChIP-chip analysis: In all cases, hybridization data for ChIP fraction was compared with that of SUP (supernatant) fraction. Pombe whole chromosome array was used.

2010-06-10 | E-GEOD-5257 | biostudies-arrayexpress

Mapping of cohesion factor association sites in S. cerevisiae - Meiosis I chromosome segregation is established through regulation of microtubule-kinetochore interactions.

Project description:During meiosis, a single round of DNA replication is followed by two consecutive rounds of nuclear divisions called meiosis I and meiosis II. In meiosis I, homologous chromosomes segregate, while sister chromatids remain together. Determining how this unusual chromosome segregation behavior is established is central to understanding germ cell development. 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. 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. Furthermore we find that restricting outer kinetochore assembly contributes to preventing premature engagement of microtubules with kinetochores. 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. The association of the cohesion factors Rec8, Pds5, and Sgo1 were measured by ChIP-chip analysis in wild-type and CUP-CLB3 strains.

2012-10-05 | E-GEOD-41339 | biostudies-arrayexpress

Mapping of cohesion factor association sites in S. cerevisiae - Meiosis I chromosome segregation is established through regulation of microtubule-kinetochore interactions.

2012-10-05 | GSE41339 | GEO

Aurora A kinase phosphorylates Hec1 to regulate metaphase kinetochore-microtubule dynamics.

Project description:Precise regulation of kinetochore-microtubules is essential for successful chromosome segregation. Central to this regulation is Aurora B kinase, which phosphorylates kinetochore substrates to promote microtubule turnover. A critical target of Aurora B is the N-terminal “tail” domain of Hec1/NDC80, which is a component of the NDC80 complex, a force-transducing link between kinetochores and microtubules. While Aurora B is regarded as the “master regulator” of kinetochore-microtubule attachment, it is likely that other mitotic kinases contribute to Hec1phosphorylation. Here we show that Aurora A kinase phosphorylates the tail domain of Hec1 at Serine 69, a previously uncharacterized phosphorylation target site, and plays an important role in controlling kinetochore-microtubule attachment dynamics. Using phospho-specific antibodies, Hec1 phospho-deficient mutants, and kinase inhibitors, we demonstrate that Aurora A is required for the regulation of kinetochore-microtubule dynamics of metaphase chromosomes and identify Hec1 Serine 69 as a critical Aurora A substrate for this regulation. Additionally, we demonstrate that Aurora A kinase associates with INCENP during mitosis and that INCENP is competent to drive accumulation of the kinase to the centromere region of mitotic chromosomes. These findings reveal that both Aurora A and Aurora B contribute to kinetochore-microtubule attachment dynamics, and they uncover an unexpected role for Aurora A in mitosis.

2017-11-28 | PXD006892 | Pride

CX-MS of Phospho-regulated Bim1/EB1 interactions trigger Dam1c ring assembly at the budding yeast outer kinetochore

Project description:Kinetochores form the link between chromosomes and microtubules of the mitotic spindle. The heterodecameric Dam1 complex (Dam1c) is a major component of the S. cerevisiae outer kinetochore, assembling into 3 MDa-sized microtubule-embracing rings, but how ring assembly is specifically initiated at kinetochores remains to be understood. Here, we describe a molecular pathway that provides local control of ring assembly during the establishment of sister kinetochore bi-orientation. We show that Dam1c and the general microtubule plus-end-associated protein (+TIP) Bim1/EB1 form a stable complex depending on a conserved motif in the Duo1 subunit of Dam1c. EM analyses reveal that Bim1 crosslinks protrusion domains of adjacent Dam1c heterodecamers and promotes the formation of oligomers with defined curvature. Disruption of the Dam1c-Bim1 interaction impairs kinetochore localization of Dam1c in metaphase and delays mitosis. Phosphorylation promotes Dam1c-Bim1 binding by relieving an intramolecular inhibition of the Dam1 C-terminus. In addition, Bim1 recruits Bik1/CLIP-170 to Dam1c and induces formation of full rings even in the absence of microtubules. Our data help to explain how new kinetochore end-on attachments are formed during the process of attachment error correction.

2021-06-28 | PXD026935 | Pride

Monopolar attachment of sister kinetochores at meiosis I requires casein kinase 1.

Project description:The segregation of maternal centromeres away from the paternal ones during the first division of meiosis depends on the attachment of sister kinetochores to microtubules emanating from the same spindle pole. In budding yeast monopolar attachment requires the recruitment to kinetochores of a protein complex called monopolin. The biochemical function of monopolin was unknown. Here, we have identified the casein kinase I Hrr25 as a hitherto unknown subunit of monopolin. Hrr25 differs from other monopolin components by its enzymatic activity and strong evolutionary conservation. We demonstrate that Hrr25’s kinase activity and its interaction with monopolin are both required for monopolar attachment. Accordingly, Hrr25 is associated with centromeres in meiosis I. Our results revealed a surprising new role for casein kinases and provide a hypothesis for the mechanism of monopolar attachment during meiosis I in sexually reproducing organisms: casein kinase I-dependent phosphorylation of kinetochore proteins. Keywords: ChIP-chip, Meiosis, Cell cycle, Saccharomyces cerevisiae, Chromosome VI tiling array, Hrr25, Mam1

2006-09-23 | GSE4792 | GEO

SUMOylation regulates the metaphase-anaphase transition by stabilizing sister kinetochore biorientation

Project description:The accurate segregation of chromosomes during mitosis relies on the attachment of sister chromatids to microtubules from opposite poles, called biorientation. Sister chromatid cohesion resists microtubule forces, generating tension which provides the signal that biorientation has occurred. How tension silences the surveillance pathways that prevent cell cycle progression and correct erroneous kinetochore-microtubule remains unclear. Here we identify SUMOylation as a mechanism that promotes anaphase onset upon biorientation. SUMO ligases modify the tension-sensing pericentromere-localized chromatin protein, shugoshin, to stabilize bioriented sister kinetochore-microtubule attachments and allow entry into anaphase. SUMOylation of shugoshin prevents binding to protein phosphatase 2A (PP2A), while enhancing chromosome passenger complex (CPC) interaction and removal from centromeres. Dissociation of the shugoshin-PP2A interaction is important for stabilizing sister kinetochore biorientation. Therefore, SUMOylation modulates protein interactions within pericentromeres to allow a signalling switch in response to biorientation.

2021-05-06 | PXD015565 | Pride

The proteomic landscape of centromeric chromatin reveals an essential role for the Ctf19 complex in meiotic kinetochore assembly.

Project description:Faithful gamete formation during meiosis requires that kinetochores take on new functions that impact homolog pairing/recombination and their attachments to microtubules. We used a proteomics pipeline to determine the global composition of centromeric chromatin and kinetochores at distinct meiotic stages. Our datasets uncover an unanticipated role for the Ctf19CCAN inner kinetochore sub-complex in gametogenesis. We show that components of the Ctf19 complex that are dispensable for mitotic growth become critical for assembly of a functional kinetochore upon meiotic entry. Consequently, in the absence of these factors, chromosomes fail to attach to meiotic spindles and produce inviable gametes due to gross segregation errors. Our evidence suggests that functional kinetochore assembly is driven by Ctf19CCAN complex-dependent Ipl1AURORA B positioning at the inner kinetochore. Thus, our global view of kinetochore composition in meiosis reveals the extent of kinetochore remodelling during gametogenesis and uncovers a kinetochore assembly pathway that becomes critical in meiosis.

2021-02-23 | PXD019754 | Pride

Shugoshin biases chromosomes for biorientation through condensin recruitment to the pericentromere

Project description:To protect against aneuploidy, chromosomes must attach to microtubules from opposite poles (“biorientation”) prior to their segregation during mitosis. Biorientation relies on the correction of erroneous attachments by the aurora B kinase, which destabilizes kinetochore-microtubule attachments that lack tension. Incorrect attachments are also avoided because sister kinetochores are intrinsically biased towards capture by microtubules from opposite poles. Here we show that shugoshin acts as a pericentromeric adaptor that plays dual roles in biorientation in budding yeast. Shugoshin maintains the aurora B kinase at kinetochores that lack tension, thereby engaging the error correction machinery. Shugoshin also recruits the chromosome-organising complex, condensin, to the pericentromere. Pericentromeric condensin biases sister kinetochores towards capture by microtubules from opposite poles. Overall, shugoshin integrates a bias to sister kinetochore capture with error correction to enable chromosome biorientation. Our findings uncover the molecular basis of the bias to sister kinetochore capture and expose shugoshin as a pericentromeric hub controlling chromosome biorientation.

2014-01-08 | GSE53856 | GEO

Centromeric chromatin in mitosis reorganizes into a functional structure stabilized by cohesin [CENPA-ChIP-seq]

Project description:Three-dimensional organization of mitotic chromosomes is established by cohesin and condensin complexes. In the centromere, cohesin maintains sister chromatid pairing until anaphase onset, while condensin provides elastic resistance to spindle forces. However, how condensin and cohesin structure vertebrate centromeres remains unclear. By super-resolution imaging, Capture-C analysis and polymer modeling we show that vertebrate centromeres are partitioned into two condensin-dependent subdomains during mitosis. This bipartite sub-structure is found in human, mouse and chicken centromeres, and is therefore a fundamental feature of vertebrate centromere. Super-resolution imaging and electron tomography reveal that bipartite centromeres assemble bipartite kinetochores with each subdomain capable of binding a distinct microtubule bundle. Cohesin helps to link the centromere subdomains, limiting their separation in response to spindle forces and preventing merotelic attachments. The two-domain structure described here may have implications for avoiding chromosomal instability as uncoupling of centromere subdomains is a common feature of lagging chromosomes in cancer cells.

2024-04-01 | GSE254181 | GEO

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