Cohesin residency determines chromatin loop patterns
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ABSTRACT:
PROVIDER: PRJNA635793 | ENA |
REPOSITORIES: ENA
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Project description:Cohesin residency determines chromatin loop patterns
| PRJNA636358 | ENA
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: Not available
| S-EPMC7655110 | biostudies-literature
Project description:The spatial organization of chromosomes influences many nuclear processes including gene expression. The cohesin complex shapes the 3D genome by looping together CTCF sites along chromosomes. We show here that chromatin loop size can be increased, and that the duration with which cohesin embraces DNA determines the degree to which loops are enlarged. Cohesin’s DNA release factor WAPL restricts the degree of this loop extension and also prevents looping between incorrectly oriented CTCF sites. We reveal that the SCC2/SCC4 complex promotes the extension of chromatin loops and the formation of topologically associated domains (TADs). Our data support the model that cohesin structures chromosomes through the processive enlargement of loops and that TADs reflect polyclonal collections of loops in the making. Finally, we find that whereas cohesin promotes chromosomal looping, it rather limits nuclear compartmentalization. We conclude that the balanced activity of SCC2/SCC4 and WAPL enables cohesin to correctly structure chromosomes.
2017-05-03 | GSE94993 | GEO
Project description:The spatial organization of chromosomes influences many nuclear processes including gene expression. The cohesin complex shapes the 3D genome by looping together CTCF sites along chromosomes. We show here that chromatin loop size can be increased, and that the duration with which cohesin embraces DNA determines the degree to which loops are enlarged. Cohesin’s DNA release factor WAPL restricts the degree of this loop extension and also prevents looping between incorrectly oriented CTCF sites. We reveal that the SCC2/SCC4 complex promotes the extension of chromatin loops and the formation of topologically associated domains (TADs). Our data support the model that cohesin structures chromosomes through the processive enlargement of loops and that TADs reflect polyclonal collections of loops in the making. Finally, we find that whereas cohesin promotes chromosomal looping, it rather limits nuclear compartmentalization. We conclude that the balanced activity of SCC2/SCC4 and WAPL enables cohesin to correctly structure chromosomes.
2017-05-03 | GSE94992 | GEO
Project description:The spatial organization of chromosomes influences many nuclear processes including gene expression. The cohesin complex shapes the 3D genome by looping together CTCF sites along chromosomes. We show here that chromatin loop size can be increased, and that the duration with which cohesin embraces DNA determines the degree to which loops are enlarged. Cohesin’s DNA release factor WAPL restricts the degree of this loop extension and also prevents looping between incorrectly oriented CTCF sites. We reveal that the SCC2/SCC4 complex promotes the extension of chromatin loops and the formation of topologically associated domains (TADs). Our data support the model that cohesin structures chromosomes through the processive enlargement of loops and that TADs reflect polyclonal collections of loops in the making. Finally, we find that whereas cohesin promotes chromosomal looping, it rather limits nuclear compartmentalization. We conclude that the balanced activity of SCC2/SCC4 and WAPL enables cohesin to correctly structure chromosomes.
2017-05-03 | GSE95014 | GEO
Project description:Cohesin organizes mammalian interphase chromosomes by reeling chromatin fibers into dynamic loops. "Loop extrusion" is obstructed when cohesin encounters a properly oriented CTCF protein. It has been proposed that transcription relocalizes or interferes with cohesin, and that active transcription start sites function as cohesin loading sites, but how these effects, and transcription in general, shape chromatin is unknown. To determine whether transcription can modulate loop extrusion, we studied cells in which the primary extrusion barriers could be removed by CTCF depletion and cohesin’s residence time and abundance on chromatin could be increased by Wapl knockout. We found evidence that transcription directly interacts with loop extrusion through a novel "moving barrier" mechanism, but not by loading cohesin at active promoters. Hi-C experiments showed intricate, cohesin-dependent genomic contact patterns near actively transcribed genes, and in CTCF-Wapl double knockout (DKO) cells, genomic contacts were enriched between sites of transcription-driven cohesin localization ("cohesin islands"). Similar patterns also emerged in polymer simulations in which transcribing RNA polymerases (RNAPs) acted as "moving barriers" by impeding, slowing, or pushing loop-extruding cohesins. The model predicts that cohesin does not load preferentially at promoters and instead accumulates at TSSs due to the barrier function of RNAPs. We tested this prediction by new ChIP-seq experiments, which revealed that the "cohesin loader" Nipbl co-localizes with cohesin, but, unlike in previous reports, Nipbl did not accumulate at active promoters. We propose that RNAP acts as a new type of barrier to loop extrusion that, unlike CTCF, is not stationary in its precise genomic position, but is itself dynamically translocating and relocalizes cohesin along DNA. In this way, loop extrusion could enable translocating RNAPs to maintain contacts with distal regulatory elements, allowing transcriptional activity to shape genomic functional organization.
2023-03-13 | GSE196621 | 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:Cohesin loss eliminates all loop domains
| PRJNA412386 | ENA