Saccharomyces cerevisiae
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ABSTRACT:
PROVIDER: PRJNA105875 | ENA |
REPOSITORIES: ENA
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Project description:The chromosomal condensin complex gives metaphase chromosomes structural stability. In addition, condensin is required for sister chromatid resolution during their segregation in anaphase. How condensin promotes chromosome resolution is poorly understood. Chromosome segregation during anaphase also fails after inactivation of topoisomerase II (topo II), the enzyme that removes catenation between sister chromatids left behind after completion of DNA replication. This has led to the proposal that condensin promotes DNA decatenation, but direct evidence for this is missing and alternative roles for condensin in chromosome resolution have been suggested. Using the budding yeast rDNA as a model, we now show that anaphase bridges in a condensin mutant are resolved by ectopic expression of a foreign (Chlorella virus) but not endogenous topo II. This suggests that catenation prevents sister rDNA segregation, and that yeast topo II is ineffective in decatenating the locus without condensin. Condensin and topo II colocalize along both rDNA and euchromatin, consistent with coordination of their activities. We investigate the physiological consequences of condensin-dependent rDNA decatenation and find that late decatenation determines the late segregation timing of this locus during anaphase. Regulation of decatenation therefore provides a means to finetune segregation timing of chromosomes in mitosis. Keywords: ChIP-chip, Cell Cycle
2008-07-18 | GSE11988 | GEO
Project description:Crosslinking-MS analysis of Saccharomyces cerevisiae cohesin complex with or without binding with Mrc1.
2023-05-04 | PXD039609 | JPOST Repository
Project description:Successful meiotic recombination, and thus fertility, depends on conserved axis proteins that organize chromosomes into arrays of anchored chromatin loops and provide a protected environment for DNA exchange. Here, we show that the stereotypic chromosomal distribution of axis proteins in S. cerevisiae is the additive result of two independent pathways: a cohesin-dependent pathway, which was previously identified and mediates focal enrichment of axis proteins at gene ends, and a parallel cohesin-independent pathway that recruits axis proteins to broad genomic islands with high gene density. These islands exhibit elevated markers of crossover recombination as well as increased nucleosome density, which we show is a direct consequence of the underlying DNA sequence. A predicted PHD domain in the center of the axis factor Hop1 specifically mediates cohesin-independent axis recruitment. Intriguingly, other chromosome organizers, including cohesin, condensin, and topoisomerases, are differentially depleted from the same regions even in non-meiotic cells, indicating that these DNA sequence-defined chromatin islands exert a general influence on the patterning of chromosome structure.
2022-04-08 | GSE156040 | GEO
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 Structural Maintenance of Chromosomes (SMC) complexes regulate the chromosome structures essential for proper genome regulation and cell viability. In mammals, the coordinated actions of the SMC complexes condensin I, condensin II and cohesin regulate dynamic chromosome structures throughout the cell cycle, but it is not clear how these complexes are positioned across the genome. We report here that condensin I, condensin II and cohesin occupy active euchromatic regions of the embryonic stem cell genome, but not heterochromatic regions. Like cohesin, we find that condensin II is deposited at active genes by the SMC loading factor Nipbl. The recruitment of Condensin II to active genes is dependent on their transcriptional activation. Subsequent transcriptional elongation by RNA polymerase II distributes condensin II across gene bodies. During mitosis, condensin I occupies the same set of active genes occupied by condensin II during interphase. Thus, SMC complexes are positioned in the genome by transcription-dependent processes, indicating that condensin-dependent condensation mechanisms are preferentially utilized in euchromatic regions. RNA-seq in mES cells after known-down of Smc1, CapH2 or Smc2.
2013-10-28 | E-GEOD-46316 | biostudies-arrayexpress
Project description:Condensins are broadly conserved chromosome organizers that function in chromatin compaction and transcriptional regulation, but to what extent these two functions are linked has remained unclear. Here, we analyzed the effect of condensin inactivation on genome compaction and global gene expression in the yeast Saccharomyces cerevisiae. Spike-in-controlled 3C-seq analysis revealed that acute condensin inactivation led to a global decrease in close-range chromosomal interactions as well as more specific losses of homotypic tRNA gene clustering. In addition, we identified a condensin-rich topologically associated domain between the ribosomal DNA and the centromere on chromosome XII that is lost upon condensin inactivation. Unexpectedly, these large-scale changes in chromosome architecture were not associated with global changes in transcript levels as determined by spike-in-controlled mRNA-seq analysis. Our data suggest that the global transcriptional program of S. cerevisiae is resistant to condensin inactivation and the associated profound changes in genome organization.
2017-10-25 | GSE106104 | GEO
Project description:Condensin plays fundamental roles in chromosome dynamics. In this study, we determined the binding sites of condensin on fission yeast (Schizosaccharomyces pombe) chromosomes at the level of nucleotide sequences using chromatin immunoprecipitation (ChIP) and ChIP-sequencing (ChIP-seq). We found that condensin binds to RNA polymerase I-, II- and III-transcribed genes during both mitosis and interphase, and we focused on pol II constitutive and inducible genes. Accumulation sites for condensin are distinct from those of cohesin and DNA topoisomerase II. Using cell cycle stage- and heat shock-inducible genes, we demonstrate that pol II-mediated transcripts cause condensin accumulation. First, condensin’s enrichment on mitotically activated genes was abolished by deleting the sep1+ gene that encodes an M-phase-specific forkhead transcription factor. Second, by raising the temperature, condensin accumulation was rapidly induced at heat shock protein genes in interphase and even during mid-mitosis. In interphase, condensin accumulates preferentially during the post-replicative phase. pol II-mediated transcription was neither repressed nor activated by condensin, as levels of transcripts per se did not change when mutant condensin failed to associate with chromosomal DNA. However, massive chromosome missegregation occurred, suggesting that abundant pol II transcription may require active condensin prior to proper chromosome segregation.
2015-04-15 | GSE65956 | GEO
Project description:This project aims to identify novel RNA binding proteins in the baker's yeast, Saccharomyces cerevisiae. Since interactions between RNAs and proteins may be transient, yeast cells were crosslinked with UV light at 254 nm which promotes the covalent link between proteins and RNAs. After this, polyadenylated mRNAs were purified via oligo(dT) coupled to magentic beads under stringet conditions. Finally, samples were subjected to mass spectrometry analysis. To rule out the possibility of RNA-independent binding we also analysed other samples: i) samples digested with RNase one; ii) samples where we performed competition assays with polyadenylic acid.
2015-10-26 | PXD002293 | Pride
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.
2019-10-03 | PXD014896 | Pride