Saccharomyces cerevisiae
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ABSTRACT:
PROVIDER: PRJNA192193 | ENA |
REPOSITORIES: ENA
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Project description:During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Diminished Smc5/6 function causes severe defects in nuclear division, but the underlying causes of these defects remain unclear. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of joint-molecule intermediates. Furthermore, we find that Smc5/6 specifically promotes resolution of joint molecules via the XPF-family endonuclease, Mus81-Mms4Eme1. We propose that Smc5/6 acts as a chaperone for M-bM-^@M-^XmitoticM-bM-^@M-^Y-like recombination processes during meiosis. ChIP-chip was used to compare Smc5 localization in wild-type and spo11 strains
2013-12-27 | E-GEOD-44852 | biostudies-arrayexpress
Project description:During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Diminished Smc5/6 function causes severe defects in nuclear division, but the underlying causes of these defects remain unclear. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of joint-molecule intermediates. Furthermore, we find that Smc5/6 specifically promotes resolution of joint molecules via the XPF-family endonuclease, Mus81-Mms4Eme1. We propose that Smc5/6 acts as a chaperone for ‘mitotic’-like recombination processes during meiosis.
2013-12-27 | GSE44852 | GEO
Project description:The meiotic cohesin Rec8 is required for the stepwise segregation of chromosomes during the two rounds of meiotic division. By directly measuring chromosome compaction in living cells of the fission yeast Schizosaccharomyces pombe, we found an additional role for the meiotic cohesin in the compaction of chromosomes during meiotic prophase. In the absence of Rec8, chromosomes were decompacted relative to those of wild-type cells. Conversely, loss of the cohesin-associated protein Pds5 resulted in hyper-compaction. While this hyper-compaction requires Rec8, binding of Rec8 to chromatin was reduced in the absence of Pds5, indicating that Pds5 promotes chromosome association of Rec8. To explain these observations, we propose that meiotic prophase chromosomes are organized as chromatin loops emanating from a Rec8-containing axis; the absence of Rec8 disrupts the axis, resulting in disorganized chromosomes, whereas reduced Rec8 loading results in a longitudinally compacted axis with fewer attachment points and longer chromatin loops. Keywords: ChIP-chip analysis ChIP analysis of Rec8: In all cases, hybridization data for ChIP fraction was compared with that of SUP (supernatant) fraction. Pombe chromosome II, III array was used.
2010-07-01 | E-GEOD-5284 | biostudies-arrayexpress
Project description:The Structural Maintenance of Chromosome (SMC) protein complexes cohesin, condensin and the Smc5/6 complex (Smc5/6) are essential for chromosome function. At the molecular level, these complexes fold DNA by loop extrusion. Accordingly, cohesin creates chromosome loops in interphase, and condensin compacts mitotic chromosomes. However, the role of Smc5/6’s recently discovered DNA loop extrusion activity is unknown. Here, we uncover that Smc5/6 controls the spatial organization of supercoiled chromosomal regions. The results show that Smc5/6 associates with transcription-induced positively supercoiled chromosomal DNA at cohesin-dependent chromosome loop boundaries. Mechanistically, single-molecule imaging reveals that dimers of Smc5/6 specifically recognize the tip of positively supercoiled DNA plectonemes, and efficiently initiates loop extrusion to gather the supercoiled DNA into a large plectonemic loop. Finally, Hi-C analysis shows that Smc5/6 links chromosomal regions containing transcription-induced positive supercoiling in cis. Altogether, our findings indicate that Smc5/6 controls the three-dimensional organization of chromosomes by recognizing and initiating loop extrusion on positively supercoiled DNA.
2024-01-30 | GSE235559 | GEO
Project description:The Structural Maintenance of Chromosome (SMC) protein complexes cohesin, condensin and the Smc5/6 complex (Smc5/6) are essential for chromosome function. At the molecular level, these complexes fold DNA by loop extrusion. Accordingly, cohesin creates chromosome loops in interphase, and condensin compacts mitotic chromosomes. However, the role of Smc5/6’s recently discovered DNA loop extrusion activity is unknown. Here, we uncover that Smc5/6 controls the spatial organization of supercoiled chromosomal regions. The results show that Smc5/6 associates with transcription-induced positively supercoiled chromosomal DNA at cohesin-dependent chromosome loop boundaries. Mechanistically, single-molecule imaging reveals that dimers of Smc5/6 specifically recognize the tip of positively supercoiled DNA plectonemes, and efficiently initiates loop extrusion to gather the supercoiled DNA into a large plectonemic loop. Finally, Hi-C analysis shows that Smc5/6 links chromosomal regions containing transcription-induced positive supercoiling in cis. Altogether, our findings indicate that Smc5/6 controls the three-dimensional organization of chromosomes by recognizing and initiating loop extrusion on positively supercoiled DNA.
2024-01-30 | GSE235558 | GEO
Project description:The Structural Maintenance of Chromosome (SMC) protein complexes cohesin, condensin and the Smc5/6 complex (Smc5/6) are essential for chromosome function. At the molecular level, these complexes fold DNA by loop extrusion. Accordingly, cohesin creates chromosome loops in interphase, and condensin compacts mitotic chromosomes. However, the role of Smc5/6’s recently discovered DNA loop extrusion activity is unknown. Here, we uncover that Smc5/6 controls the spatial organization of supercoiled chromosomal regions. The results show that Smc5/6 associates with transcription-induced positively supercoiled chromosomal DNA at cohesin-dependent chromosome loop boundaries. Mechanistically, single-molecule imaging reveals that dimers of Smc5/6 specifically recognize the tip of positively supercoiled DNA plectonemes, and efficiently initiates loop extrusion to gather the supercoiled DNA into a large plectonemic loop. Finally, Hi-C analysis shows that Smc5/6 links chromosomal regions containing transcription-induced positive supercoiling in cis. Altogether, our findings indicate that Smc5/6 controls the three-dimensional organization of chromosomes by recognizing and initiating loop extrusion on positively supercoiled DNA.
2024-01-30 | GSE235557 | GEO
Project description:The meiotic cohesin Rec8 is required for the stepwise segregation of chromosomes during the two rounds of meiotic division. By directly measuring chromosome compaction in living cells of the fission yeast Schizosaccharomyces pombe, we found an additional role for the meiotic cohesin in the compaction of chromosomes during meiotic prophase. In the absence of Rec8, chromosomes were decompacted relative to those of wild-type cells. Conversely, loss of the cohesin-associated protein Pds5 resulted in hyper-compaction. While this hyper-compaction requires Rec8, binding of Rec8 to chromatin was reduced in the absence of Pds5, indicating that Pds5 promotes chromosome association of Rec8. To explain these observations, we propose that meiotic prophase chromosomes are organized as chromatin loops emanating from a Rec8-containing axis; the absence of Rec8 disrupts the axis, resulting in disorganized chromosomes, whereas reduced Rec8 loading results in a longitudinally compacted axis with fewer attachment points and longer chromatin loops. Keywords: ChIP-chip analysis
2006-08-23 | GSE5284 | GEO
Project description:Eukaryotic genomes are folded into DNA loops mediated by SMC complexes, like cohesin, condensin and Smc5/6. This organization regulates different DNA related processes along the cell cycle such as transcription, recombination, segregation and DNA repair. During G2/M phases, SMC complexes mediated DNA loops coexist with cohesin complexes involved in sister chromatid cohesion (SCC). It remains unknown whether SCC and DNA loop expansion influence each other and if they cooperate to regulate DNA-related processes. Here we show that SCC is indeed a barrier to DNA loop expansion mediated by cohesin in G2.
2024-01-30 | GSE237031 | GEO
Project description:Smc5/6 is essential for genome structural integrity by yet unknown mechanisms. Here we find that Smc5/6 co-localizes with the DNA crossed-strand processing complex Sgs1-Top3-Rmi1 (STR) at genomic regions known as natural pausing sites (NPSs) where it facilitates Top3 retention. Individual depletions of STR subunits and Smc5/6 cause similar accumulation of joint molecules (JMs) composed of reversed forks, double Holliday Junctions and hemicatenanes, indicative of Smc5/6 regulating Sgs1 and Top3 DNA processing activities. We isolate an intra-allelic suppressor of smc6-56 proficient in Top3 retention but affected in pathways that act complementarily with Sgs1 and Top3 to resolve JMs arising at replication termination. Upon replication stress, the smc6-56 suppressor requires STR and Mus81-Mms4 functions for recovery, but not Srs2 and Mph1 helicases that prevent maturation of recombination intermediates. Thus, Smc5/6 functions jointly with Top3 and STR to mediate replication completion and influences the function of other DNA crossed-strand processing enzymes at NPSs.
2021-02-03 | GSE147452 | GEO
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