Saccharomyces cerevisiae
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA95731 | ENA |
REPOSITORIES: ENA
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Project description:Segregation of homologous maternal and paternal centromeres to opposite poles during meiosis I depends on post-replicative crossing over between homologous non-sister chromatids, which creates chiasmata and therefore bivalent chromosomes. Destruction of sister chromatid cohesion along chromosome arms due to proteolytic cleavage of cohesin's Rec8 subunit by separase resolves chiasmata and thereby triggers the first meiotic division. This produces univalent chromosomes, the chromatids of which are held together by centromeric cohesin that has been protected from separase by shugoshin (Sgo1/MEI-S332) proteins. Here we show in both fission and budding yeast that Sgo1 recruits to centromeres a specific form of protein phosphatase 2A (PP2A). Its inactivation causes loss of centromeric cohesin at anaphase I and random segregation of sister centromeres at the second meiotic division. Artificial recruitment of PP2A to chromosome arms prevents Rec8 phosphorylation and hinders resolution of chiasmata. Our data are consistent with the notion that efficient cleavage of Rec8 requires phosphorylation of cohesin and that this is blocked by PP2A at meiosis I centromeres. Keywords: ChIP-chip, Mitosis, Meiosis, Cell cycle, Saccharomyces cerevisiae, Chromosome VI tiling array, Sgo1, Pp2A, Cse4, Ndc10, Rts1, Rec8
2006-05-10 | GSE4791 | GEO
Project description:Sister chromatid cohesion establishment by acetylation
| PRJNA106243 | ENA
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 attachments 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. In the absence of SUMOylation, Aurora B kinase removal from kinetochores is delayed. Shugoshin SUMOylation prevents its binding to protein phosphatase 2A (PP2A) and release of this interaction is important for stabilizing sister kinetochore biorientation. We propose that SUMOylation modulates the kinase-phosphatase network within pericentromeres to inactivate the error correction machinery, thereby allowing anaphase entry in response to biorientation.
2021-03-25 | PXD019287 | Pride
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
Project description:The ring-shaped cohesin complex links sister chromatids until their timely segregation during mitosis. Cohesin is enriched at centromeres, where it provides the cohesive counter-force to bi-polar tension produced by the mitotic spindle. As a consequence of spindle tension, centromeric sequences transiently split in pre-anaphase cells, in some organisms up to several micrometeres. This ‘centromere breathing’ presents a paradox, how sister sequences separate where cohesin is most enriched. We now show that in the budding yeast S. cerevisiae, cohesin binding diminishes over centromeric sequences that split during breathing. We see no evidence for cohesin translocation to surrounding sequences, suggesting that cohesin is removed from centromeres during breathing. Two pools of cohesin can be distinguished. Cohesin loaded before DNA replication, that has established sister chromatid cohesion, disappears during breathing. In contrast, cohesin loaded after DNA replication is partly retained. As sister centromeres re-associate after transient separation, cohesin is re-loaded in a manner independent of the canonical cohesin loader Scc2/Scc4. Efficient centromere re-association requires the cohesion establishment factor Eco1, suggesting that re-establishment of sister chromatid cohesion contributes to the dynamic behaviour of centromeres in mitosis. These findings provide new insights into cohesin behaviour at centromeres. Keywords: ChIP-chip
2007-09-30 | GSE8661 | GEO
Project description:Centromeres play several important roles in ensuring proper chromosome segregation. Not only do they promote kinetochore assembly for microtubule attachment, but they also support robust sister chromatid cohesion at pericentromeres and facilitate replication of centromeric DNA early in S phase. However, it is still elusive how centromeres orchestrate all these functions at the same site. Here we show that the budding yeast Dbf4-dependent kinase (DDK) accumulates at kinetochores in telophase, facilitated by the Ctf19 kinetochore complex. This promptly recruits Sld3-Sld7 replication initiator proteins to pericentromeric replication origins so that they initiate replication early in S phase. Furthermore DDK at kinetochores independently recruits the Scc2-Scc4 cohesin loader to centromeres in G1 phase. This enhances cohesin loading and facilitates robust pericentromeric cohesion in S phase. Thus, we have found the central mechanism by which kinetochores orchestrate early S phase DNA replication and robust sister chromatid cohesion at microtubule attachment sites. Measurement of genome replication time for various S. cerevisiae strains. For each strain two samples were analysed: a replicating sample (from S phase) and a non-replicating sample (from G2 phase).
2013-06-06 | E-GEOD-41982 | biostudies-arrayexpress
Project description:Cohesion between sister chromatids depends on the chromosomal cohesin complex and allows the spindle apparatus in mitosis to recognize replicated chromosomes for segregation into daughter cells. Sister chromatid cohesion is established concomitant with DNA replication, and requires the essential Eco1 protein, a replication fork-associated acetyl transferase. The mechanism by which Eco1 establishes sister chromatid cohesion is not known. Here, we show that the cohesin subunit Smc3 is acetylated in an Eco1-dependent manner during S phase to establish sister chromatid cohesion. We isolated spontaneous suppressors of the thermosensitive eco1-1 allele in budding yeast, and identified the suppressor mutations from the hybridization pattern of genomic DNA on oligonucleotide tiling arrays. An acetylation mimicking mutation of a conserved lysine in Smc3 to asparagine (K113N) makes Eco1 dispensable for cell growth, indicating that Smc3 acetylation is Eco1’s only essential function. We identified a second set of eco1-1 suppressor mutations in the budding yeast ortholog of the cohesin regulator Wapl (Wpl1/Rad61). Wapl destabilizes cohesin on chromosomes, and Eco1-dependent Smc3 acetylation during S-phase might render cohesin resistant to Wapl. Our results clarify the role of Eco1 in the establishment of sister chromatid cohesion, and suggest that Eco1 modifies cohesin to stabilize an Eco1-independent cohesion establishment reaction.
2008-07-24 | GSE11527 | GEO
Project description:FACT mediates cohesin function on chromatin Cohesin is a key regulator of genome architecture with roles in sister chromatid cohesion and the organisation of higher-order structures during interphase and mitosis. The recruitment and mobility of cohesin complexes on DNA are restricted by nucleosomes. Here we show that cohesin role in chromosome organization requires the histone chaperone FACT. Depletion of FACT in metaphase cells affects cohesin stability on chromatin reducing its accumulation at pericentric regions and binding on chromosome arms. Using Hi-C, we show that cohesin-dependent TAD (Topological Associated Domains)-like structures in G1 and metaphase chromosomes are disrupted in the absence of FACT. Surprisingly, sister chromatid cohesion is intact in FACT-depleted cells, although chromosome segregation failure is observed. Our results uncover a role for FACT in genome organisation by facilitating cohesin dependent compartmentalization of chromosomes into loop domains.
2019-10-03 | PXD014896 | Pride
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
Project description:Centromeres play several important roles in ensuring proper chromosome segregation. Not only do they promote kinetochore assembly for microtubule attachment, but they also support robust sister chromatid cohesion at pericentromeres and facilitate replication of centromeric DNA early in S phase. However, it is still elusive how centromeres orchestrate all these functions at the same site. Here we show that the budding yeast Dbf4-dependent kinase (DDK) accumulates at kinetochores in telophase, facilitated by the Ctf19 kinetochore complex. This promptly recruits Sld3-Sld7 replication initiator proteins to pericentromeric replication origins so that they initiate replication early in S phase. Furthermore DDK at kinetochores independently recruits the Scc2-Scc4 cohesin loader to centromeres in G1 phase. This enhances cohesin loading and facilitates robust pericentromeric cohesion in S phase. Thus, we have found the central mechanism by which kinetochores orchestrate early S phase DNA replication and robust sister chromatid cohesion at microtubule attachment sites.
2013-06-06 | GSE41982 | GEO