Condensin II Counters Cohesin and RNA Polymerase II in 3D Chromatin Organization
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ABSTRACT:
PROVIDER: PRJNA486736 | ENA |
REPOSITORIES: ENA
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Project description:CTCF is present at the anchors of thousands of loops likely formed via cohesin-mediated loop extrusion in mammalian cells. Interaction domains present in D. melanogaster chromosomes form via the segregation of active and inactive chromatin in the absence of CTCF looping, but the role of transcription versus other architectural proteins in chromatin organization is unclear. Here we find that positioning of RNAPII via transcription elongation is essential in the formation of gene loops, which in turn interact to form compartmental domains. Inhibition of transcription elongation or depletion of cohesin decreases gene looping and formation of active compartmental domains. In contrast, depletion of condensin II, which also localizes to active chromatin, results in increased gene looping, formation of compartmental domains, and stronger intra-chromosomal compartmental interactions. Condensin II has a similar role in maintaining inter-chromosomal interactions responsible for pairing between homologous chromosomes, whereas inhibition of transcription elongation or cohesin depletion has little effect on homolog pairing. The results suggest distinct roles for cohesin and condensin II in the establishment of 3D nuclear organization in Drosophila.
2019-03-11 | GSE118756 | GEO
Project description: Not available
| S-EPMC6424357 | biostudies-literature
Project description:The role of condensin II in genome organization
| PRJNA317761 | ENA
Project description:Condensin molecules are loaded onto the genome to mediate essential changes in chromosome condensation during mitosis, but it is not clear why there are two forms of vertebrate condensin that become differentially distributed on chromosomes. We report here that condensin II, the form of condensin present in the nucleus throughout the cell cycle, functions specifically at active genes. Condensin II is loaded at transcriptionally active promoters in embryonic stem cells (ESCs), migrates through these genes in a transcription-dependent fashion and accumulates in transcription termination regions. Unlike cohesin, which is also loaded at active promoters, condensin II has little influence on transcription. We conclude that condensin II is loaded and distributed across actively transcribed chromatin and thus serves to specifically condense this euchromatic portion of chromosomes during the cell division cycle. ChIP-Seq data for Condensin II and Cohesin in v6.5 ESCs treated or not with the RNA polymerase II elongation inhibitor flavopiridol.
2012-02-09 | E-GEOD-30919 | biostudies-arrayexpress
Project description:The dramatic change in morphology of chromosomal DNAs between interphase and mitosis is one of the defining features of the eukaryotic cell cycle. Two types of enzymes, namely cohesin and condensin confer the topology of chromosomal DNA by extruding DNA loops. While condensin normally configures chromosomes exclusively during mitosis, cohesin does so during interphase. The processivity of cohesin’s loop extrusion during interphase is limited by a regulatory factor called WAPL, which induces cohesin to dissociate from chromosomes via a mechanism that requires dissociation of its kleisin from the neck of SMC3. We show here that a related mechanism may be responsible for blocking condensin II from acting during interphase. Cells derived from patients affected by microcephaly caused by mutations in the MCPH1 gene undergo premature chromosome condensation but it has never been established for certain whether MCPH1 regulates condensin II directly. We show that deletion of Mcph1 in mouse embryonic stem cells unleashes an activity of condensin II that triggers formation of compact chromosomes in G1 and G2 phases, which is accompanied by enhanced mixing of A and B chromatin compartments, and that this occurs even in the absence of CDK1 activity. Crucially, inhibition of condensin II by MCPH1 depends on the binding of a short linear motif within MCPH1 to condensin II’s NCAPG2 subunit. We show that the activities of both Cohesin and Condensin II may be restricted during interphase by similar types of mechanisms as MCPH1’s ability to block condensin II’s association with chromatin is abrogated by the fusion of SMC2 with NCAPH2. Remarkably, in the absence of both WAPL and MCPH1, cohesin and condensin II transform chromosomal DNAs of G2 cells into chromosomes with a solenoidal axis showing that both cohesin and condensin must be tightly regulated to adjust the structure of chromatids for their successful segregation.
2021-11-19 | GSE188988 | GEO
Project description:Condensin complexes are highly conserved for chromosome compaction to ensure their faithful segregation in mitosis. However, little is known about the role of condensin complexes in interphase. Condensins exists in two complexes, condensins I and II, in higher eukayotic cells. During interphase, condensin II is predominantly localized in the nucleus throughout the cell cycle, whereas condensin I is localized at the cytoplasm in interphase. The distinct localization patterns suggest that condensin II, but not condensin I, may contribute to genome organization in interphase. Our results suggest that condensin II is associated with TFIIIC complex in vivo. The aim of these experiments is to unravel the dependency of each other on binding to chromatin.
2017-06-01 | GSE80034 | GEO
Project description:Condensin complexes are known for their importance in chromosome condensation during mitosis. However, condensin II binds to the geome during interphase as well. The role of condensin II in genome organization in mammalian interphase nuclei is not characterized. Since condensin II binds to the promoters of the transcriptionally active promoters in interphase genome, the aim of this study is to uncover its role in mediating chromatin interactions between active gene promoters such as histone gene loci.
2017-06-01 | GSE80219 | GEO
Project description:Cohesin is a well-known mediator of sister chromatid cohesion, but it also influences gene expression and development. These non-canonical roles of cohesin are not well understood, but are vital: gene expression and development are altered by modest changes in cohesin function that do not disrupt chromatid cohesion. To clarify cohesinM-bM-^@M-^Ys roles in transcription, we measured how cohesin controls RNA polymerase II (Pol II) activity by genome-wide chromatin immunoprecipitation and precision global run-on sequencing. On average, cohesin-binding genes have more transcriptionally active Pol II and promoter-proximal Pol II pausing than non-binding genes, and are more efficient, producing higher steady state levels of mRNA per transcribing Pol II complex. Cohesin depletion frequently increases pausing at cohesin-binding genes, indicating that cohesin often facilitates transition of paused Pol II to elongation. In many cases this likely reflects a role for cohesin in transcriptional enhancer function. Strikingly, more than 95% of predicted extragenic enhancers bind cohesin, and cohesin depletion can reduce their association with Pol II, indicating that cohesin facilitates enhancer-promoter contact. Cohesin directly promotes transcription of the myc gene, and cohesin depletion reduces Pol II activity at most Myc target genes. The multiple transcriptional roles of cohesin revealed by these studies likely underlie the growth and developmental deficits caused by minor changes in cohesin activity. We performed ChIP-chip of Rpb3 (representing total Pol II), Ser2P-Pol II (representing elongating Pol II), and Cdk12 and CycT Pol II kinase components in Mock RNAi-treated and cohesin subunit Rad21 RNAi-treated ML-DmBG3-c2 cells, which revealed that cohesin depletion has a variety of effects on Pol II occupancy and modification, as well as on occupancy of Pol II kinases.
2013-04-24 | E-GEOD-42360 | biostudies-arrayexpress
Project description:Condensin complexes are highly conserved for chromosome compaction to ensure their faithful segregation in mitosis. However, little is known about the role of condensin complexes in interphase. Condensins exists in two complexes, condensins I and II, in higher eukayotic cells. During interphase, condensin II is predominantly localized in the nucleus throughout the cell cycle, whereas condensin I is localized at the cytoplasm in interphase. The distinct localization patterns suggest that condensin II, but not condensin I, may contribute to genome organization in interphase. Our results suggest that condensin II is associated with TFIIIC complex in humans.
2018-09-05 | GSE119418 | GEO
Project description:Cohesin is a well-known mediator of sister chromatid cohesion, but it also influences gene expression and development. These non-canonical roles of cohesin are not well understood, but are vital: gene expression and development are altered by modest changes in cohesin function that do not disrupt chromatid cohesion. To clarify cohesin’s roles in transcription, we measured how cohesin controls RNA polymerase II (Pol II) activity by genome-wide chromatin immunoprecipitation and precision global run-on sequencing. On average, cohesin-binding genes have more transcriptionally active Pol II and promoter-proximal Pol II pausing than non-binding genes, and are more efficient, producing higher steady state levels of mRNA per transcribing Pol II complex. Cohesin depletion frequently increases pausing at cohesin-binding genes, indicating that cohesin often facilitates transition of paused Pol II to elongation. In many cases this likely reflects a role for cohesin in transcriptional enhancer function. Strikingly, more than 95% of predicted extragenic enhancers bind cohesin, and cohesin depletion can reduce their association with Pol II, indicating that cohesin facilitates enhancer-promoter contact. Cohesin directly promotes transcription of the myc gene, and cohesin depletion reduces Pol II activity at most Myc target genes. The multiple transcriptional roles of cohesin revealed by these studies likely underlie the growth and developmental deficits caused by minor changes in cohesin activity. The PRO-seq method was used to measure transcriptionally engaged Pol II genome-wide in two replicates each of mock RNAi-treated, Nipped-B RNAi-treated, and Rad21 RNAi-treated ML-DmBG3-c2 cells.
2013-04-24 | E-GEOD-42397 | biostudies-arrayexpress