Saccharomyces cerevisiae
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ABSTRACT:
PROVIDER: PRJNA379912 | ENA |
REPOSITORIES: ENA
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Project description:Sister chromatid cohesion relies on cohesins, a group of proteins that forms a ring-shaped complex embracing sister chromatids. Cohesion is established during S phase and is removed when cohesin Scc1 is cleaved by the protease separase at anaphase onset. During this process, the cohesin subunit Smc3 undergoes a cycle of acetylation: Smc3 acetylation by Eco1 in S phase stabilizes cohesin association with chromosomes, and its deacetylation by Hos1 in anaphase allows re-use of Smc3 in the next cell cycle. Here we find that Smc3 deacetylation by Hos1 has a more immediate effect in early anaphase of budding yeast. Without Hos1, sister chromatid separation and segregation are significantly delayed. Smc3 deacetylation facilitates removal of cohesins from chromosomes, without changing the Scc1 cleavage efficiency, thus promoting dissolution of cohesion. This action is probably due to disengagement of Smc1–3 heads, prompted by de-repression of their ATPase activity. We suggest Scc1 cleavage per se is insufficient for efficient dissolution of cohesion in early anaphase, but subsequent Smc3 deacetylation, which is triggered by Scc1 cleavage, is also required.
2017-11-02 | GSE96841 | GEO
Project description:Cohesion between sister chromatids is mediated by the chromosomal cohesin complex. In budding yeast, cohesin is loaded onto chromosomes during the G1 phase of the cell cycle. During S-phase, the replication fork-associated acetyltransferase Eco1 acetylates the cohesin subunit Smc3 to promote establishment of sister chromatid cohesion. At the time of anaphase, Smc3 loses its acetylation again, but the Smc3 deacetylase and possible importance of Smc3 deacetylation are unknown. Here, we show that the class I histone deacetylase family member Hos1 is responsible for Smc3 deacetylation. Cohesin is protected from deacetylation while bound to chromosomes, but is deacetylated as soon as it dissociates from chromosomes following separase cleavage at anaphase onset. Non-acetylated Smc3 is required as a substrate for cohesion establishment in the following cell cycle. Our results complete the description of the Smc3 acetylation cycle and provide unexpected insight into the importance of de novo Smc3 acetylation for cohesion establishment.
2010-06-10 | GSE22257 | GEO
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:Cohesin is a multisubunit complex that mediates sister-chromatid cohesion. Its Smc1 and Smc3 subunits possess ABC-like ATPases at one end of 50 nm long coiled coils. At the other ends are pseudosymmetrical hinge domains that interact to create V-shaped Smc1/Smc3 heterodimers. N- and C-terminal domains within cohesin's kleisin subunit Scc1 bind to Smc3 and Smc1 ATPase heads respectively, thereby creating a huge tripartite ring. It has been suggested that cohesin associates with chromosomes by trapping DNA within its ring. Opening of the ring due to cleavage of Scc1 by separase destroys sister-chromatid cohesion and triggers anaphase. We show that cohesin's hinges are not merely dimerization domains. They are essential for cohesin's association with chromosomes, which is blocked by artificially holding hinge domains together but not by preventing Scc1's dissociation from SMC ATPase heads. Our results suggest that entry of DNA into cohesin's ring requires transient dissociation of Smc1 and Smc3 hinge domains. Keywords: Cohesin loading, Scc1, Smc1, Smc3, Hinge opening, ChIP-chip
2006-11-05 | GSE4827 | GEO
Project description:Sister chromatid cohesion conferred by entrapment of sister DNAs within a tripartite ring formed between cohesinâs Scc1, Smc1, and Smc3 subunits is generated during S and eventually destroyed at anaphase through cleavage of Scc1 by separase. Throughout the cell cycle, cohesinâs association with chromosomes is controlled by opposing activities: loading by the Scc2/4 complex and release by a separase independent releasing activity. Co-entrapment of sister DNAs during replication is accompanied by acetylation of Smc3 by Eco1, which blocks releasing activity and ensures that sisters remain stably connected. Because fusion of Smc3 to Scc1 prevents release and bypasses the requirement for Eco1, we suggested that release is mediated by disengagement of the Smc3/Scc1 interface. We now show that all mutations capable of bypassing Eco1, be they in cohesinâs Smc1, Smc3, Scc1,Wapl, Pds5, or Scc3 subunits, greatly reduce dissociation of N-terminal cleavage fragments of Scc1 (NScc1) from Smc3. We show that this process involves interaction between Smc ATPase heads and is inhibited by Smc3 acetylation Effect of mutations QQ and EQ in Smc3 on cohesin loading onto chromosomes
2016-02-18 | E-GEOD-76890 | biostudies-arrayexpress
Project description:Sister chromatid cohesion conferred by entrapment of sister DNAs within a tripartite ring formed between cohesin’s Scc1, Smc1, and Smc3 subunits is generated during S and eventually destroyed at anaphase through cleavage of Scc1 by separase. Throughout the cell cycle, cohesin’s association with chromosomes is controlled by opposing activities: loading by the Scc2/4 complex and release by a separase independent releasing activity. Co-entrapment of sister DNAs during replication is accompanied by acetylation of Smc3 by Eco1, which blocks releasing activity and ensures that sisters remain stably connected. Because fusion of Smc3 to Scc1 prevents release and bypasses the requirement for Eco1, we suggested that release is mediated by disengagement of the Smc3/Scc1 interface. We now show that all mutations capable of bypassing Eco1, be they in cohesin’s Smc1, Smc3, Scc1,Wapl, Pds5, or Scc3 subunits, greatly reduce dissociation of N-terminal cleavage fragments of Scc1 (NScc1) from Smc3. We show that this process involves interaction between Smc ATPase heads and is inhibited by Smc3 acetylation
2016-02-18 | GSE76890 | GEO
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:Chromosome segregation requires both the separation of sister chromatids and the sustained condensation of chromatids during anaphase. In yeast cells, cohesin is not only required for sister chromatid cohesion but also plays a major role in determining the structure of individual chromatids in metaphase. Separase cleavage is thought to remove all cohesin complexes from chromosomes to initiate anaphase. It is thus not clear how the length and organisation of segregating chromatids are maintained during anaphase in the absence of cohesin. Here we show that degradation of cohesin at the anaphase onset causes aberrant chromatid segregation. Hi-C analysis on segregating chromatids demonstrates that cohesin depletion causes loss of intrachromatid organisation. Surprisingly, TEV-mediated cleavage of cohesin does not dramatically disrupt chromatid organisation in anaphase, explaining why bulk segregation is achieved. In addition, we identified a small pool of cohesin complexes bound to telophase chromosomes in wildtype cells and show that they play a role in the organisation of centromeric regions. Our data demonstrate that in yeast cells, cohesin function is not over in metaphase, but extends to the anaphase period when chromatids are segregating.
2022-10-01 | GSE183481 | GEO
Project description:To ensure equal separation of DNA, sister chromatids are held together from S phase to metaphase–anaphase transition by a multiprotein complex called cohesin. This makes it possible to establish chromosome biorientation, counteracts the pulling force of mitotic spindle microtubules, preventing premature sister chromatid separation, and ensures precise segregation of sister DNAs into daughter cells In order to better understand how the sister chromatid cohesion process is regulated we looked for new cohesin interacors. We constructed a yeast strain endogenously expressing TAP-tagged Scc1 (Scc1-TAP). Next, we performed a single-step TAP purification using an untagged strain (mock sample) or a strain expressing Scc1-TAP, followed by identification of co-purifying proteins by MS.
2023-10-24 | PXD037034 | Pride
Project description:DNA replication during S-phase is accompanied by establishment of sister chromatid cohesion to ensure faithful chromosome segregation. The Eco1 acetyltransferase, helped by factors including Ctf4 and Chl1, concomitantly acetylates the chromosomal cohesin complex to stabilize its cohesive links. Here we show that Ctf4 recruits the Chl1 helicase to the replisome via a conserved interaction motif that Chl1 shares with GINS and polymerase α. We visualize recruitment by EM analysis of a reconstituted Chl1-Ctf4-GINS assembly. The Chl1 helicase facilitates replication fork progression under conditions of nucleotide depletion, however this function does not require Ctf4 interaction. Conversely, Ctf4 interaction, but not helicase activity, is required for Chl1’s role in sister chromatid cohesion. A physical interaction between Chl1 and the cohesin complex during S-phase suggests that Chl1 contacts cohesin to facilitate its acetylation. Our results reveal how Ctf4 forms a replisomal interaction hub that coordinates replication fork progression and sister chromatid cohesion establishment.
2016-04-08 | GSE80007 | GEO