THE SPATIAL REGULATION OF CONDENSIN ACTIVITY IN CHROMOSOME CONDENSATION
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PROVIDER: PRJNA613686 | ENA |
REPOSITORIES: ENA
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Project description:Condensin mediates chromosome condensation, which is essential for proper chromosome segregation during mitosis. Prior to anaphase of budding yeast, the ribosomal DNA (RDN) condenses to a thin loop that is distinct from the rest of the chromosomes. We provide evidence that the establishment and maintenance of this RDN condensation require the regulation of condensin by Cdc5p (polo) kinase. We show that Cdc5p is recruited to the site of condensin binding in the RDN by cohesin, a complex related to condensin. Cdc5p and cohesin prevent condensin from misfolding the RDN into an irreversibly decondensed state. From these and other observations, we propose that the spatial regulation of Cdc5p by cohesin modulates condensin activity to ensure proper RDN folding into a thin loop. This mechanism may be evolutionarily conserved, promoting the thinly condensed constrictions that occur at centromeres and RDN of mitotic chromosomes in plants and animals.
2020-05-03 | GSE147290 | GEO
Project description:The experiment was performed to assess the importance of nucleosome eviction for the binding of condensin to chromatin during mitosis. The condensin complex associates with chromatin during mitosis to ensure chromosome condensation and accurate segregation, but how this binding is achieved remains poorly understood. Our study indicates that transcription co-activators Gcn5 and Mst2 assist condensin binding during mitosis by evicting nucleosomes. To reach this conclusion, we mapped nucleosomes, during mitosis, in wild-type and gcn5mst2 mutant strains. This experiment allowed us (1) to identify nucleosome-depleted regions (ndrs) during mitosis and to show that condensin tends to colocalize with ndr at the 3ends of genes, and (2) to confirm the importance of nucleosome eviction from ndrs by gcn5 and mst2, during mitosis, for the binding of condensin to chromatin.this experiment determines the patterns of nucleosomes in wild type and mutant fission yeast cells arrested in early mitosis. We analysed wild-type cells, cells lacking Gcn5 histone acetylatransferase (gcn5D) and cells lacking both Gcn5 and Mst2 histone acetyltransferases (Gcn5Dmst2D). All cells used in this study expressed a GFP-tagged version of condensin (Cnd2-GFP) and were blocked in early mitosis at 19C by the nda3-KM311 mutation. Mitotic indexes were determined by scoring the accumulation of Cnd2-GFP in the nucleus. Mitotic cells were collected and chromatin was digested by increasing amount of MNase to produce mononucleosomes. Mononucleosomal DNA was purified on an agarose gel and sequence on an Illumina Nextseq 500 apparatus. Three replicates of wild type, gcn5D and gcn5Dmst2D were analysed. Nucleosome patterns were determined in wild-type cells, cells lacking Gcn5 and cells lacking both Gcn5 and Mst2.
2016-04-18 | E-MTAB-4620 | biostudies-arrayexpress
Project description:Nucleosome eviction in mitosis assists condensin loading and chromosome condensation
| PRJEB13354 | ENA
Project description:Condensin is a conserved SMC complex that uses its ATPase machinery to structure genomes, but how it does so is largely unknown. We show that condensin’s ATPase has a dual role in chromosome condensation. Mutation of one ATPase site impairs condensation, while mutating the second site results in hyperactive condensin that compacts DNA faster than wild type, both in vivo and in vitro. Whereas one site drives loop formation, the second site is involved in the formation of more stable higher-order Z loop structures. Using hyperactive condensin I, we reveal that condensin II is not intrinsically needed for the shortening of mitotic chromosomes. Condensin II rather is required for a straight chromosomal axis and enables faithful chromosome segregation by counteracting the formation of ultrafine DNA bridges. SMC complexes with distinct roles for each ATPase site likely reflect a universal principle that enables these molecular machines to intricately control chromosome architecture.
2019-10-16 | GSE108774 | GEO
Project description: Not available
| S-EPMC7263143 | biostudies-literature
Project description:Chromatin fibres dynamically change their organisation during cell cycle. In interphase nucleus, chromatin fibres are evenly distributed whereas their spatial occupancy are reorganised to form condensed chromosomes in mitosis. This process called chromosome condensation is necessary for an accomplishment of faithful chromosome segregation. One of the Structural Maintenance of Chromosomes complexes, Condensin, is indispensable for chromosome condensation. It remains, however, unknown how Condensin plays its role in shaping mitotic chromosome. Here we show that chromatin fibres change their interacting partners; short-range contacts in interphase nucleus are converted into long-range interactions to shape condensed chromosomes. This conversion of interactions among chromatin fibres results in the formation of larger domains within mitotic chromosomes. Condensin is solely in charge of the conversion and large domain formation in fission yeast mitosis. Our results show how fission yeast Condensin is involved in shaping mitotic chromosomes.
2017-07-13 | GSE94475 | GEO
Project description:Chromatin fibres dynamically change their organisation during cell cycle. In interphase nucleus, chromatin fibres are evenly distributed whereas their spatial occupancy are reorganised to form condensed chromosomes in mitosis. This process called chromosome condensation is necessary for an accomplishment of faithful chromosome segregation. One of the Structural Maintenance of Chromosomes complexes, Condensin, is indispensable for chromosome condensation. It remains, however, unknown how Condensin plays its role in shaping mitotic chromosome. Here we show that chromatin fibres change their interacting partners; short-range contacts in interphase nucleus are converted into long-range interactions to shape condensed chromosomes. This conversion of interactions among chromatin fibres results in the formation of larger domains within mitotic chromosomes. Condensin is solely in charge of the conversion and large domain formation in fission yeast mitosis. Our results show how fission yeast Condensin is involved in shaping mitotic chromosomes.
2017-07-13 | GSE94474 | GEO
Project description:Vertebrate condensin I and II molecules are loaded onto the genome to mediate essential changes in chromosome condensation during mitosis, but it is not clear how the two forms of condensin become distributed on chromosomes. We report here that condensin II, the form of condensin present in the nucleus throughout the cell cycle, is loaded at transcriptionally active promoters, migrates through these genes in a transcription-dependent fashion and accumulates in transcription termination regions during interphase. During mitosis, condensin I is recruited to actively transcribed genes and replaces condensin II. We conclude that the two forms of condensin are loaded at different times during the cell division cycle at the promoters of actively transcribed genes. ChIP-Seq data for Condensin II in v6.5 ESCs treated or not with nocodazole
2012-03-14 | E-GEOD-33346 | biostudies-arrayexpress
Project description:ABSTRACT: Condensin is a central regulator of mitotic genome structure, with mutants showing poorly condensed chromosomes and profound segregation defects. Here we identify the fission yeast NCT complex, comprising the Nrc1 BET-family tandem bromodomain protein (SPAC631.02), Casein Kinase II (CKII) and several TAFs, as a novel regulator of condensin function (where NCT mutants restore the formation of segregation-competent chromosomes in cells containing defective condensin). Synchronous ChIP-seq shows that NCT and condensin bind similar genomic regions, but only briefly co-localize during the periods of chromosome condensation and decondensation. These results are consistent with a model where NCT targets CKII to chromatin in a cell cycle-directed manner to modulate the activity of condensin during chromosome condensation and decondensation. DATA: Study includes ChIP-seq of fission yeast H3-K4Me3, H3-K36Me3, TBP, Taf7, Nrc1, Cka1 from aynchronous cells; Nrc1 and Cut3 (representing condensin) from four synchronized cell-cycle stages estimated as G2/M, Metaphase, Anaphase and G1/S.
2014-01-10 | E-GEOD-53955 | biostudies-arrayexpress
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