Evidence that Loading of Cohesin Onto Chromosomes Involves Opening of Its SMC Hinge
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE4827 | GEO | 2006/11/05
SECONDARY ACCESSION(S): PRJNA95639
REPOSITORIES: GEO
Similar Datasets
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: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: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 â?¢ Experimental factors Distribution of the mutant and wild type form of cohesin in mitotic G2 phase. â?¢ Experimental design ChIP analysis: In all cases, hybridization data for ChIP fraction was compared with SUP (supernatant) fraction. SUP fraction is equal to WCE (Whole Cell Extract) fraction. Essentially WCE or SUP fraction of any cell cycle phase can be used for normalization, and there was no effect on protein binding profiles. Cerevisiae chromosome VI array was used. â?¢ Quality control steps taken Confirmation using different tags. Confirmation by q-PCR. Checking of the ChIP fraction by Western blotting. Mock hybridisation of samples immuno-precipitated from cells containing no tag recognized by antibody used. Samples used, extract preparation and labelling: â?¢ The origin of each biological sample Saccharomyces cerevisiae (W303). â?¢ Manipulation of biological samples and protocols used Chromatin immunoprecipitation (ChIP) and hybridization to Affimetrix high-density oligonucleotide arrays of S. cerevisiae chromosome VIwere performed essentially as previously described (Katou et al., 2003, nature) (Lengronne et al., 2004, nature). â?¢ Technical protocols for preparing the hybridization extract The chromatin-immunprecipates were eluted and incubated over night at 65ºC to reverse the cross-link. Immunoprecipitated genomic DNA was incubated with proteinase K, extracted 2 times with phenol/chloroform/isoamylalcohol, precipitated, resuspended in TE and incubated with RnaseA. The DNA was then purified using the Qiagen PCR purification kit, and concentrated by ethanol precipitation. The DNA was amplified by PCR after random priming. 10 ug of amplified DNA was digested with Dnase I to a mean size of 100 bp. After Dnase I inactivation at 95ºC. DNA fragments were end-labeled by addition of 25 U of Terminal Transferase and 1 nmol Biotin-N6ddATP (NEN) for 1 hour at 37ºC as previously described by Winzeler et al. (Science. 281, 1194-1197, 1998). The entire sample was used for hybridization. â?¢ Hybridization procedures and parameters: Hybridization, blocking and washing were carried out as previously described (Lengronne et al. Nature 2004). Each sample was hybridized to the array in 150 ul containing 6xSSPE; 0.005% TritonX-100; 15 ug fragmented denatured salmon sperm DNA (Gibco-BRL); 1 nmole 3â??biotin labelled control oligonucleotide (oligo B2, Affymetrix). Samples were denatured at 100ºC for 10 minutes, and then put on ice before being hybridized for 16 hours at 42ºC in a hybridization oven (GeneChip Hybridization Oven 640, Affymetrix). Washing and scanning protocol provided by Affymetrix was performed automatically on a fluidics station (GeneChip fluidics station 450, Affymetrix). â?¢ Measurement data and specifications: Arrays were scanned using the Genechip Scanner3000 7G following the library array description. All the cel files data and processed data files can be downloaded from GEO database. The primary analysis of tiling chip data was performed following exactly the statistical algorithm used for Affymetrix GeneChip Operating Software (GCOS). The detailed information for the algorithm used can be downloaded from the Affymetrix web site. The analysis is available on request. For the ChrVI array, one unit for analysis (locus) was set to 300bp. Fold change value, change p-value, and detection p-value for each locus were obtained by primary analysis. For the discrimination of positive and negative signals for the binding, we used three criteria as follows. First, the reliability of the signal strength was judged by detection p-value of each locus (p-valueâ?¤0.025). Secondly, reliability of binding ratio was judged by change p-value (p-valueâ?¤0.025). Thirdly, clusters consisting of at least 900bp contiguous loci that satisfied the above two criteria were selected, because it is known that a single site of protein-DNA interaction resulted in immuno-precipitation of DNA fragments that hybridized not only to the locus of the actual binding site but also to its neighbors. â?¢ Array Design: General array design: in situ synthesized arrays by Affymetrix Availability of arrays: commercially available from Affymetrix Location and ID of each spot on arrays: available from Affymetrix on request Probe type: oligonucleotide The arrays used in this study can be purchased from Affymetrix: Chromosome VI S.cerevisiae: rikDACFC6, P/N# 510636
2010-06-09 | E-GEOD-4827 | biostudies-arrayexpress
Project description:As predicted by the notion that sister chromatid cohesion is mediated by entrapment of sister DNAs inside cohesin rings, there is a perfect correlation between co-entrapment of circular minichromosomes and sister chromatid cohesion. In most cells where cohesin loads onto chromosomes but fails to form cohesion, loading is accompanied by entrapment of individual DNAs. However, cohesin with a hinge whose positively charged lumen has been neutralized not only loads onto and translocates along chromatin but also organizes it into chromatid-like threads, despite largely failing to entrap DNAs inside its ring. Thus, cohesin engages chromatin in both a non-topological and a topological manner. Further, mutation of three highly conserved lysines within the Smc1 hinge abolishes all loading without affecting cohesin’s initial recruitment to centromers or its ability to hydrolyze ATP. We suggest that loading and translocation are mediated by conformational changes in cohesin’s hinge driven by cycles of ATP hydrolysis.
2018-04-23 | GSE105005 | GEO
Project description:Cohesin connects CTCF binding sites and other genomic loci in cis to form chromatin loops, and replicated DNA molecules in trans to mediate sister chromatid cohesion. Whether cohesin uses distinct or related mechanisms to perform these functions is unknown. Here we describe a cohesin hinge mutant, which can extrude DNA into loops but is unable to mediate cohesion. Our results suggest that the latter defect arises during cohesion establishment. The observation that cohesin’s cohesion and loop extrusion activities can be separated indicates that cohesin uses distinct mechanisms to perform these two functions. Unexpectedly, the same hinge mutant can also not be stopped by CTCF boundaries as well as wildtype cohesin. This suggests that cohesion establishment and cohesin’s interaction with CTCF boundaries depend on related mechanisms and raises the possibility that both require transient hinge opening to entrap DNA inside the cohesin ring.
2023-10-25 | GSE235771 | GEO
Project description:Cohesin connects CTCF binding sites and other genomic loci in cis to form chromatin loops, and replicated DNA molecules in trans to mediate sister chromatid cohesion. Whether cohesin uses distinct or related mechanisms to perform these functions is unknown. Here we describe a cohesin hinge mutant, which can extrude DNA into loops but is unable to mediate cohesion. Our results suggest that the latter defect arises during cohesion establishment. The observation that cohesin’s cohesion and loop extrusion activities can be separated indicates that cohesin uses distinct mechanisms to perform these two functions. Unexpectedly, the same hinge mutant can also not be stopped by CTCF boundaries as well as wildtype cohesin. This suggests that cohesion establishment and cohesin’s interaction with CTCF boundaries depend on related mechanisms and raises the possibility that both require transient hinge opening to entrap DNA inside the cohesin ring.
2023-10-25 | GSE235770 | GEO
Project description:The ring-shaped cohesin complex is thought to fulfil its roles in sister chromatid cohesion, genome stability and gene regulation by topologically encircling DNAs. The ring is formed by two Structural Maintenance of Chromosome (SMC) subunits, whose ATPase heads are linked by a kleisin subunit. Additional components, including the Mis4Scc2/NIPL cohesin loader, engage the kleisin. We applied crosslinking mass spectrometry to characterize cohesion complex in two conditions: initial binding and gripping state.
2020-08-04 | PXD018608 | Pride
Project description:Cohesin’s association with and translocation along chromosomal DNAs depend on an ATP hydrolysis cycle driving the association and subsequent release of DNA. This involves DNA being ‘clamped’ by Scc2 and ATP-dependent engagement of cohesin’s Smc1 and Smc3 head domains. Scc2’s replacement by Pds5 abrogates cohesin’s ATPase and has an important role in halting DNA loop extrusion. The ATPase domains of all SMC proteins are separated from their hinge dimerisation domains by 50 nm long coiled coils, which have been observed to zip up along their entire length and fold around an elbow, thereby greatly shortening the distance between hinges and ATPase heads. Whether folding exists in vivo or has any physiological importance is not known. We present here a cryo-EM structure of the apo form of cohesin that reveals the structure of folded and zipped up coils in unprecedented detail and shows that Scc2 can associate with Smc1’s ATPase head even when it is fully disengaged from that of Smc3. Using cysteine-specific cross-linking, we show that cohesin’s coiled coils are frequently folded in vivo, including when cohesin holds sister chromatids together. Moreover, we describe a mutation (SMC1D588Y) within Smc1’s hinge that alters how Scc2 and Pds5 interact with Smc1’s hinge and that enables Scc2 to support loading in the absence of its normal partner Scc4. The mutant phenotype of loading without Scc4 is only explicable if loading depends on an association between Scc2/4 and cohesin’s hinge, which in turn requires coiled coil folding.
2021-07-21 | GSE167318 | 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