Project description:Cohesin is a key regulator of genome architecture with roles in sister chromatid cohesion and the organisation of higher-order structures during interphase and mitosis. The recruitment and mobility of cohesin complexes on DNA are restricted by nucleosomes. Here we show that cohesin role in chromosome organization requires the histone chaperone FACT. Depletion of FACT in metaphase cells affects cohesin stability on chromatin reducing its accumulation at pericentric regions and binding on chromosome arms. Using Hi-C, we show that cohesin-dependent TAD (Topological Associated Domains)-like structures in G1 and metaphase chromosomes are disrupted in the absence of FACT. Surprisingly, sister chromatid cohesion is intact in FACT-depleted cells, although chromosome segregation failure is observed. Our results uncover a role for FACT in genome organisation by facilitating cohesin dependent compartmentalization of chromosomes into loop domains.
Project description:FACT mediates cohesin function on chromatin Cohesin is a key regulator of genome architecture with roles in sister chromatid cohesion and the organisation of higher-order structures during interphase and mitosis. The recruitment and mobility of cohesin complexes on DNA are restricted by nucleosomes. Here we show that cohesin role in chromosome organization requires the histone chaperone FACT. Depletion of FACT in metaphase cells affects cohesin stability on chromatin reducing its accumulation at pericentric regions and binding on chromosome arms. Using Hi-C, we show that cohesin-dependent TAD (Topological Associated Domains)-like structures in G1 and metaphase chromosomes are disrupted in the absence of FACT. Surprisingly, sister chromatid cohesion is intact in FACT-depleted cells, although chromosome segregation failure is observed. Our results uncover a role for FACT in genome organisation by facilitating cohesin dependent compartmentalization of chromosomes into loop domains.
Project description:The cohesin complex has crucial roles in many structural and functional aspects of chromosomes including sister chromatid cohesion, genome organization, gene transcription and DNA repair. Cohesin recruitment onto chromosomes requires nucleosome free DNA and a specialized cohesin loader complex comprised of the Scc2 and Scc4 subunits. The cohesin loader, in addition to stimulating cohesin ATP hydrolysis and facilitating topological loading onto DNA, leads cohesin to chromatin receptors such as the RSC chromatin remodeling complex. Here, we explore the cohesin loader-RSC interaction and show that its Scc4 subunit contacts a conserved RSC ATPase motor module. The cohesin loader enhances RSC chromatin remodeling activity in vitro, as well as promoter nucleosome eviction in vivo. These findings provide insight into how the cohesin loader recognizes, as well as influences, the chromatin landscape, with implications for our understanding of human developmental disorders including Cornelia de Lange and Coffin-Siris syndromes.
Project description:The DNA-binding protein CTCF and the cohesin complex function together to shape chromatin architecture in mammalian cells, but the molecular details of this process remain unclear. We demonstrate that a 79 amino acid region within the CTCF N-terminal domain but not the C-terminus is necessary for cohesin positioning at CTCF binding sites and chromatin loop formation. However, the N-terminus of CTCF, when fused to artificial zinc fingers that do not bind to CTCF DNA binding sites was not sufficient to redirect cohesin to different genomic locations, indicating that cohesin positioning by CTCF does not involve direct protein-protein interactions with cohesin subunits. BORIS (CTCFL), a germline-specific paralog of CTCF was unable to anchor cohesin to CTCF DNA binding sites. Furthermore, CTCF-BORIS Chimeric constructs provided evidence that both the first two CTCF zinc fingers and, likely, the 3D geometry of CTCF-DNA complexes are involved in cohesin retention. Moreover, we were able to convert BORIS into CTCF with respect to cohesin positioning, thus providing additional molecular details of the cohesin retention function of CTCF. Our data suggest that the N-terminus of CTCF and the 3D spatial conformation of the CTCF-DNA complex act as a roadblock to constrain cohesin movement along DNA.
Project description:One bottleneck in understanding the principles of 3D chromatin structures is caused by the paucity of known regulators. Cohesin is essential for 3D chromatin organization, and its interacting partners are candidate regulators. Here, we performed proteomic profiling of the Cohesin in chromatin and identified transcription factors, RNA-binding proteins, and chromatin regulators associated with Cohesin. Acute protein degradation followed by time-series genomic binding quantitation and BAT Hi-C analysis were conducted, and the results showed that the transcription factor ZBTB21 contributes to Cohesin chromatin binding, 3D chromatin interactions and transcriptional repression. Strikingly, multiomic analyses revealed that the other four ZBTB factors interacted with Cohesin, and double degradation of ZBTB21 and ZBTB7B led to a further decrease in Cohesin chromatin occupancy. We propose that multiple ZBTB transcription factors orchestrate the chromatin binding of Cohesin to regulate chromatin interactions, and we provide a catalog of many additional proteins associated with Cohesin that warrant further investigation.
Project description:One bottleneck in understanding the principles of 3D chromatin structures is caused by the paucity of known regulators. Cohesin is essential for 3D chromatin organization, and its interacting partners are candidate regulators. Here, we performed proteomic profiling of the Cohesin in chromatin and identified transcription factors, RNA-binding proteins, and chromatin regulators associated with Cohesin. Acute protein degradation followed by time-series genomic binding quantitation and BAT Hi-C analysis were conducted, and the results showed that the transcription factor ZBTB21 contributes to Cohesin chromatin binding, 3D chromatin interactions and transcriptional repression. Strikingly, multiomic analyses revealed that the other four ZBTB factors interacted with Cohesin, and double degradation of ZBTB21 and ZBTB7B led to a further decrease in Cohesin chromatin occupancy. We propose that multiple ZBTB transcription factors orchestrate the chromatin binding of Cohesin to regulate chromatin interactions, and we provide a catalog of many additional proteins associated with Cohesin that warrant further investigation.
Project description:One bottleneck in understanding the principles of 3D chromatin structures is caused by the paucity of known regulators. Cohesin is essential for 3D chromatin organization, and its interacting partners are candidate regulators. Here, we performed proteomic profiling of the Cohesin in chromatin and identified transcription factors, RNA-binding proteins, and chromatin regulators associated with Cohesin. Acute protein degradation followed by time-series genomic binding quantitation and BAT Hi-C analysis were conducted, and the results showed that the transcription factor ZBTB21 contributes to Cohesin chromatin binding, 3D chromatin interactions and transcriptional repression. Strikingly, multiomic analyses revealed that the other four ZBTB factors interacted with Cohesin, and double degradation of ZBTB21 and ZBTB7B led to a further decrease in Cohesin chromatin occupancy. We propose that multiple ZBTB transcription factors orchestrate the chromatin binding of Cohesin to regulate chromatin interactions, and we provide a catalog of many additional proteins associated with Cohesin that warrant further investigation.