Sister chromatid cohesion halts DNA loop expansion
Ontology highlight
ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae W303
PROVIDER: GSE237031 | GEO | 2024/01/30
REPOSITORIES: GEO
Similar Datasets
Project description:The organization of chromatin into higher-order structures is essential for chromosome segregation, the repair of DNA damage, and the regulation of gene expression. These structures are formed by the evolutionarily conserved SMC (structural maintenance of chromosomes) complexes. By analyzing synchronized populations of budding yeast with Micro-C, we observed that chromatin loops are formed genome-wide, and are dependent upon the SMC complex, cohesin. We correlated the loop signal with the position and intensity of cohesin binding to chromosomes in wild-type and cells depleted for the cohesin regulators Wpl1p and Pds5p. We generate a model to explain how the genomic distribution and frequency of loops are driven by cohesin residency on chromosomes. In this model a dynamic pool of cohesin with loop extrusion activity stops when encounters two regions occupied by stably bound cohesin, forming a loop. Different regions are occupied by cohesin in different cells, defining different patterns of chromatin loops.
2020-11-04 | GSE151553 | GEO
Project description:The organization of chromatin into higher-order structures is essential for chromosome segregation, the repair of DNA damage, and the regulation of gene expression. These structures are formed by the evolutionarily conserved SMC (structural maintenance of chromosomes) complexes. By analyzing synchronized populations of budding yeast with Micro-C, we observed that chromatin loops are formed genome-wide, and are dependent upon the SMC complex, cohesin. We correlated the loop signal with the position and intensity of cohesin binding to chromosomes in wild-type and cells depleted for the cohesin regulators Wpl1p and Pds5p. We generate a model to explain how the genomic distribution and frequency of loops are driven by cohesin residency on chromosomes. In this model a dynamic pool of cohesin with loop extrusion activity stops when encounters two regions occupied by stably bound cohesin, forming a loop. Different regions are occupied by cohesin in different cells, defining different patterns of chromatin loops.
2020-11-04 | GSE151416 | GEO
Project description:Cohesin is a DNA translocase instrumental in the folding of the genome into chromatin loops, with functional consequences on DNA-related processes. Chromatin loop length and organization likely depend on cohesin processivity, translocation rate, and stability on DNA. Here we investigate and provide a comprehensive overview of the roles of various cohesin regulators in tuning chromatin loop expansion. We demonstrate that Scc2, which stimulates cohesin ATPase activity, is also essential for cohesin translocation, driving loop expansion in vivo. Smc3 acetylation during S-phase counteracts this activity through the stabilization of Pds5, which finely tunes the size and stability of loops in G2.
2022-02-23 | GSE186987 | 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 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:Structural maintenance of chromosomes (SMC) complexes shape the genomes of virtually all organisms but how they function remains incompletely understood. Recent studies in bacteria and eukaryotes have led to a unifying model in which these ring-shaped ATPases act along contiguous DNA segments processively enlarging DNA loops. In support of this model, single-molecule imaging experiments indicate that Saccharomyces cerevisiae condensin complexes can extrude DNA loops in an ATP hydrolysis dependent manner in vitro. Here, using time-resolved high-throughput chromosome conformation capture (Hi-C) we investigate the interplay between ATPase activity of the Bacillus subtilis SMC complex and loop formation in vivo. We show that point mutants in the SMC nucleotide binding domain that impair but do not eliminate ATPase activity not only exhibit delays in de novo loop formation but also have reduced rates of processive loop enlargement. These data provide in vivo evidence that SMC complexes function as loop extruders.
2018-08-09 | GSE95137 | GEO
Project description:Structural maintenance of chromosomes (SMC) complexes play critical roles in chromosome dynamics in virtually all organisms but how they function remains poorly understood. In Bacillus subtilis, SMC condensin complexes are topologically loaded at centromeric sites adjacent to the replication origin. Here we provide evidence that these ring-shaped assemblies tether the left and right chromosome arms together while traveling from the origin to the terminus (>2 Mb) at rates >50kb/min. Condensin movement scales linearly with time arguing for an active transport mechanism. These data support a model in which SMC complexes function by processively enlarging DNA loops. Loop formation followed by processive enlargement provides a mechanism for how condensin complexes compact and resolve sister chromatids in mitosis and how cohesin generates topologically associating domains (TADs) during interphase.
2017-02-03 | GSE85612 | GEO
Project description:Cohesin structures the genome through the formation of chromatin loops and by holding together the sister chromatids. The acetylation of cohesin’s SMC3 subunit is a dynamic process that involves the acetyltransferase ESCO1 and deacetylase HDAC8. Here we show that this cohesin acetylation cycle controls the 3D genome. ESCO1 restricts the length of chromatin loops and architectural stripes, while HDAC8 promotes the extension of such loops and stripes. This role in controlling loop length turns out to be distinct from the canonical role of cohesin acetylation that protects against WAPL-mediated DNA release. We reveal that acetylation rather controls cohesin’s interaction with PDS5A to restrict chromatin loop length. Our data supports a model in which this PDS5A-bound state acts as a brake that enables the pausing and restart of loop enlargement. The cohesin acetylation cycle hereby provides punctuation in the process of genome folding.
2022-03-14 | PXD032185 | Pride
Project description:Structural maintenance of chromosomes (SMC) complexes, cohesin, condensin and Smc5/6, are essential for viability and participate in multiple processes, including sister chromatid cohesion, chromosome condensation, and DNA repair. Here we show that SUMO chains target all three SMC complexes and are antagonized by the SUMO protease Ulp2 to prevent their turnover. We uncover that the essential role of the cohesin-associated subunit Pds5 is to counteract SUMO chains jointly with Ulp2. Importantly, fusion of Ulp2 to kleisin Scc1 supports viability of PDS5 null cells and protects cohesin from proteasomal degradation mediated by the SUMO-targeted ubiquitin ligase Slx5/Slx8. The lethality of PDS5 deleted cells can also be bypassed by simultaneous loss of the PCNA unloader, Elg1, and the cohesin releaser, Wpl1, but only when Ulp2 is functional. Condensin and Smc5/6 complex are similarly guarded by Ulp2 against unscheduled SUMO-chain assembly, which we propose to time the availability of SMC complexes on chromatin.
2021-08-05 | PXD022717 | Pride