Prophase pathway-dependent removal of cohesin from human chromosomes requires opening of the Smc3-Scc1 gate.
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ABSTRACT:
SUBMITTER: Buheitel J
PROVIDER: S-EPMC3590994 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Cohesin's Smc1, Smc3, and kleisin subunits create a tripartite ring within which sister DNAs are entrapped. Evidence suggests that DNA enters through a gate created by transient dissociation of the Smc1/3 interface. Release at the onset of anaphase is triggered by proteolytic cleavage of kleisin. Less well understood is the mechanism of release at other stages of the cell cycle, in particular during prophase when most cohesin dissociates from chromosome arms in a process dependent on the regulatory subunit Wapl. We show here that Wapl-dependent release from salivary gland polytene chromosomes during interphase and from neuroblast chromosome arms during prophase is blocked by translational fusion of Smc3's C-terminus to kleisin's N-terminus. Our findings imply that proteolysis-independent release of cohesin from chromatin is mediated by Wapl-dependent escape of DNAs through a gate created by transient dissociation of the Smc3/kleisin interface. Thus, cohesin's DNA entry and exit gates are distinct.
| S-EPMC3590983 | biostudies-literature
Project description:Sister chromatid cohesion, which is mediated by the cohesin complex, is essential for the proper segregation of chromosomes in mitosis and meiosis. The establishment of stable sister chromatid cohesion occurs during DNA replication and involves acetylation of the complex by the acetyltransferase CTF7. In higher eukaryotes, the majority of cohesin complexes are removed from chromosomes during prophase. Studies in fly and human have shown that this process involves the WAPL mediated opening of the cohesin ring at the junction between the SMC3 ATPase domain and the N-terminal domain of cohesin's ?-kleisin subunit. We report here the isolation and detailed characterization of WAPL in Arabidopsis thaliana. We show that Arabidopsis contains two WAPL genes, which share overlapping functions. Plants in which both WAPL genes contain T-DNA insertions show relatively normal growth and development but exhibit a significant reduction in male and female fertility. The removal of cohesin from chromosomes during meiotic prophase is blocked in Atwapl mutants resulting in chromosome bridges, broken chromosomes and uneven chromosome segregation. In contrast, while subtle mitotic alterations are observed in some somatic cells, cohesin complexes appear to be removed normally. Finally, we show that mutations in AtWAPL suppress the lethality associated with inactivation of AtCTF7. Taken together our results demonstrate that WAPL plays a critical role in meiosis and raises the possibility that mechanisms involved in the prophase removal of cohesin may vary between mitosis and meiosis in plants.
| S-EPMC4102442 | biostudies-literature
Project description:Cohesins are vital for chromosome organisation during meiosis and mitosis. In addition to the important function in sister chromatid cohesion, these complexes play key roles in meiotic recombination, DSB repair, homologous chromosome pairing and segregation. Egg-laying mammals (monotremes) feature an unusually complex sex chromosome system, which raises fundamental questions about organisation and segregation during meiosis. We discovered a dynamic and differential accumulation of cohesins on sex chromosomes during platypus prophase I and specific reorganisation of the sex chromosome complex around a large nucleolar body. Detailed analysis revealed a differential loading of SMC3 on the chromatin and chromosomal axis of XY shared regions compared with the chromatin and chromosomal axes of asynapsed X and Y regions during prophase I. At late prophase I, SMC3 accumulation is lost from both the chromatin and chromosome axes of the asynaptic regions of the chain and resolves into subnuclear compartments. This is the first report detailing unpaired DNA specific SMC3 accumulation during meiosis in any species and allows speculation on roles for cohesin in monotreme sex chromosome organisation and segregation.
| S-EPMC5484699 | biostudies-literature
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 created during S and destroyed at anaphase through Scc1 cleavage by separase. Cohesin's association with chromosomes is controlled by opposing activities: loading by Scc2/4 complex and release by a separase-independent releasing activity as well as by cleavage. Coentrapment of sister DNAs at replication is accompanied by acetylation of Smc3 by Eco1, which blocks releasing activity and ensures that sisters remain 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 show that mutations capable of bypassing Eco1 in Smc1, Smc3, Scc1, Wapl, Pds5, and Scc3 subunits reduce dissociation of N-terminal cleavage fragments of Scc1 (NScc1) from Smc3. This process involves interaction between Smc ATPase heads and is inhibited by Smc3 acetylation.
| S-EPMC4769318 | biostudies-literature
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:Sister chromatid cohesion on chromosome arms is essential for the segregation of homologous chromosomes during meiosis I while it is dispensable for sister chromatid separation during mitosis. It was assumed that, unlike the situation in mitosis, chromosome arms retain cohesion prior to onset of anaphase-I. Paradoxically, reduced immunostaining signals of meiosis-specific cohesin, including the kleisin Rec8, were observed on chromosomes during late prophase-I of budding yeast. This decrease is seen in the absence of Rec8 cleavage and depends on condensin-mediated recruitment of Polo-like kinase (PLK/Cdc5). In this study, we confirmed that this release indeed accompanies the dissociation of acetylated Smc3 as well as Rec8 from meiotic chromosomes during late prophase-I. This release requires, in addition to PLK, the cohesin regulator, Wapl (Rad61/Wpl1 in yeast), and Dbf4-dependent Cdc7 kinase (DDK). Meiosis-specific phosphorylation of Rad61/Wpl1 and Rec8 by PLK and DDK collaboratively promote this release. This process is similar to the vertebrate "prophase" pathway for cohesin release during G2 phase and pro-metaphase. In yeast, meiotic cohesin release coincides with PLK-dependent compaction of chromosomes in late meiotic prophase-I. We suggest that yeast uses this highly regulated cleavage-independent pathway to remove cohesin during late prophase-I to facilitate morphogenesis of condensed metaphase-I chromosomes.
| S-EPMC6317811 | biostudies-literature
Project description:Age-dependent oocyte aneuploidy, a major cause of Down syndrome, is associated with declining sister chromatid cohesion in postnatal oocytes. Here we show that cohesion in postnatal mouse oocytes is regulated by Tex19.1. We show Tex19.1-/- oocytes have defects maintaining chiasmata, missegregate their chromosomes during meiosis, and transmit aneuploidies to the next generation. Furthermore, we show that mouse Tex19.1 inhibits N-end rule protein degradation mediated by its interacting partner UBR2, and that Ubr2 itself has a previously undescribed role in negatively regulating the acetylated SMC3 subpopulation of cohesin in mitotic somatic cells. Lastly, we show that acetylated SMC3 is associated with meiotic chromosome axes in mouse oocytes, and that this population of cohesin is specifically depleted in the absence of Tex19.1. These findings indicate that Tex19.1 regulates UBR protein activity to maintain acetylated SMC3 and sister chromatid cohesion in postnatal oocytes and prevent aneuploidy from arising in the female germline.
| S-EPMC7199850 | biostudies-literature
Project description:Cohesin mediates sister chromatid cohesion by topologically entrapping sister DNA molecules inside its ring structure. Cohesin is loaded onto DNA by the Scc2/NIPBL-Scc4/MAU2-loading complex in a manner that depends on the adenosine triphosphatase (ATPase) activity of cohesin's Smc1 and Smc3 subunits. Subsequent cohesion establishment during DNA replication depends on Smc3 acetylation by Esco1 and Esco2 and on recruitment of sororin, which "locks" cohesin on DNA by inactivating the cohesin release factor Wapl.Human cohesin ATPase mutants associate transiently with DNA in a manner that depends on the loading complex but cannot be stabilized on chromatin by depletion of Wapl. These mutants cannot be acetylated, fail to interact with sororin, and do not mediate cohesion. The absence of Smc3 acetylation in the ATPase mutants is not a consequence of their transient association with DNA but is directly caused by their inability to hydrolyze ATP because acetylation of wild-type cohesin also depends on ATP hydrolysis.Our data indicate that cohesion establishment involves the following steps. First, cohesin transiently associates with DNA in a manner that depends on the loading complex. Subsequently, ATP hydrolysis by cohesin leads to entrapment of DNA and converts Smc3 into a state that can be acetylated. Finally, Smc3 acetylation leads to recruitment of sororin, inhibition of Wapl, and stabilization of cohesin on DNA. Our finding that cohesin's ATPase activity is required for both cohesin loading and Smc3 acetylation raises the possibility that cohesion establishment is directly coupled to the reaction in which cohesin entraps DNA.
| S-EPMC4188815 | biostudies-literature
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 is mediated by cohesin, whose Smc1, Smc3, and kleisin (Scc1) subunits form a ring structure that entraps sister DNAs. The ring is opened either by separase, which cleaves Scc1 during anaphase, or by a releasing activity involving Wapl, Scc3, and Pds5, which bind to Scc1 and open its interface with Smc3. We present crystal structures of Pds5 from the yeast L. thermotolerans in the presence and absence of the conserved Scc1 region that interacts with Pds5. Scc1 binds along the spine of the Pds5 HEAT repeat fold and is wedged between the spine and C-terminal hook of Pds5. We have isolated mutants that confirm the observed binding mode of Scc1 and verified their effect on cohesin by immunoprecipitation and calibrated ChIP-seq. The Pds5 structure also reveals architectural similarities to Scc3, the other large HEAT repeat protein of cohesin and, most likely, Scc2.
| S-EPMC4793087 | biostudies-literature