Project description:Yeast RNA polymerase (Pol) II consists of a ten-subunit core enzyme and the Rpb4/7 subcomplex, which is dispensable for catalytic activity and dissociates in vitro. To investigate whether Rpb4/7 is an integral part of DNA-associated Pol II in vivo, we used chromatin immuno-precipitation coupled to high-resolution tiling microarray analysis. We show that the genome-wide occupancy profiles for Rpb7 and the core subunit Rpb3 are essentially identical. Thus, the complete Pol II associates with DNA in vivo, consistent with functional roles of Rpb4/7 throughout the transcription cycle. Keywords: ChIP-chip Comparison of Rpb3 vs. Rpb4/7 genome-wide occupancy profiles. Data obtained from independent ChIP-chip experiments on two yeast strains: S288C Rpb3TAP vs. Rpb7-TAP strain and W303 Rpb3-TAP vs. wild type strain (IP with the monoclonal antibody for Rpb4/7). Biological replicates W303 strains: 1 x Rpb3-TAP, 1 x wt with Rpb4/7 antibody, independently grown and harvested. Biological replicates S288C strains: 3 x Rpb3-TAP, 2 x Rpb7-TAP, independently grown and harvested. One replicate per array.
Project description:Yeast RNA polymerase (Pol) II consists of a ten-subunit core enzyme and the Rpb4/7 subcomplex, which is dispensable for catalytic activity and dissociates in vitro. To investigate whether Rpb4/7 is an integral part of DNA-associated Pol II in vivo, we used chromatin immuno-precipitation coupled to high-resolution tiling microarray analysis. We show that the genome-wide occupancy profiles for Rpb7 and the core subunit Rpb3 are essentially identical. Thus, the complete Pol II associates with DNA in vivo, consistent with functional roles of Rpb4/7 throughout the transcription cycle. Keywords: ChIP-chip
Project description:THO/TREX is a conserved nuclear complex that functions in mRNP biogenesis and prevents transcription-associated recombination. Whether or not it has a ubiquitous role in the genome is an open question. ChIP-chip studies reveal that the Hpr1 component of THO and the Sub2 RNA-dependent ATPase have genome wide-distributions at active ORFs in yeast. In contrast to RNAPII, evenly distributed from promoter to termination regions, THO and Sub2 are absent at promoters and distributed in a sharp 5M-bM-^@M-^YM-bM-^FM-^R3M-bM-^@M-^Y gradient. Importantly, ChIP-chips reveal an over-recruitment of Rrm3 in active genes in THO mutants that is reduced by overexpression of RNase H1. Our work establishes a genome-wide function for THO-Sub2 in transcription elongation and mRNP biogenesis that function to prevent the accumulation of transcription-mediated replication obstacles, including R-loops. ChIP-chip studies were perfomed with tagged forms of the Hpr1 component of THO (Hpr1-FLAG), the Sub2 RNA-dependent ATPase of TREX (Sub2-FLAG), the Rpb3 subunit of RNA polymerase II (Rpb3-PK) and the Rrm3 protein (Rrm3-FLAG) in the yeast S. cerevisiae.
Project description:Paired-end sequencing study of (1) nucleosome core particles and under-digested chromatin from MNase-treated nuclei; (2) ChIP samples for HA-tagged histone H4 and H2B; (3) ChIP for the Rpb3 subunit of Pol II.
Project description:Cmr1 (changed mutation rate 1) is a largely uncharacterized nuclear protein that has recently emerged in several global genetic interaction and protein localization studies. It clusters with proteins involved in DNA damage and replication stress response, suggesting a role in maintaining genome integrity. Under conditions of proteasome inhibition or replication stress, this protein localizes to distinct sub-nuclear foci termed as intranuclear quality control (INQ) compartments, which sequester proteins for their subsequent degradation. Interestingly, it also interacts with histones, chromatin remodelers and modifiers, as well as with proteins involved in transcription including subunits of RNA Pol I and Pol III, but not with those of Pol II. It is not known whether Cmr1 plays a role in regulating transcription of Pol II target genes. Here, we show that Cmr1 is recruited to the coding regions of transcribed genes of S. cerevisiae. Cmr1 occupancy correlates with the Pol II occupancy genome-wide, indicating that it is recruited to coding sequences in a transcription-dependent manner. Cmr1-enriched genes include Gcn4 targets and ribosomal protein genes. Furthermore, our results show that Cmr1 recruitment to coding sequences is stimulated by Pol II CTD kinase, Kin28, and the histone deacetylases, Rpd3 and Hos2. Finally, our genome-wide analyses implicate Cmr1 in regulating Pol II occupancy at transcribed coding sequences. However, it is dispensable for maintaining co-transcriptional histone occupancy and histone modification (acetylation and methylation). Collectively, our results show that Cmr1 facilitates transcription by directly engaging with transcribed coding regions. ChIp-chip experiments were perfomed to determine genome-wide distribution of Cmr1 in WT and gcn4Δ cells (S. cerevisiae). Rpb3 occupancy in WT and cmr1Δ cells was also determined to reveal the changes in Pol II occupancy in the absence of Cmr1.
Project description:Cmr1 (changed mutation rate 1) is a largely uncharacterized nuclear protein that has recently emerged in several global genetic interaction and protein localization studies. It clusters with proteins involved in DNA damage and replication stress response, suggesting a role in maintaining genome integrity. Under conditions of proteasome inhibition or replication stress, this protein localizes to distinct sub-nuclear foci termed as intranuclear quality control (INQ) compartments, which sequester proteins for their subsequent degradation. Interestingly, it also interacts with histones, chromatin remodelers and modifiers, as well as with proteins involved in transcription including subunits of RNA Pol I and Pol III, but not with those of Pol II. It is not known whether Cmr1 plays a role in regulating transcription of Pol II target genes. Here, we show that Cmr1 is recruited to the coding regions of transcribed genes of S. cerevisiae. Cmr1 occupancy correlates with the Pol II occupancy genome-wide, indicating that it is recruited to coding sequences in a transcription-dependent manner. Cmr1-enriched genes include Gcn4 targets and ribosomal protein genes. Furthermore, our results show that Cmr1 recruitment to coding sequences is stimulated by Pol II CTD kinase, Kin28, and the histone deacetylases, Rpd3 and Hos2. Finally, our genome-wide analyses implicate Cmr1 in regulating Pol II occupancy at transcribed coding sequences. However, it is dispensable for maintaining co-transcriptional histone occupancy and histone modification (acetylation and methylation). Collectively, our results show that Cmr1 facilitates transcription by directly engaging with transcribed coding regions. ChIp-chip experiments were perfomed to determine genome-wide distribution of Cmr1 in WT and gcn4Î cells (S. cerevisiae). Rpb3 occupancy in WT and cmr1Î cells was also determined to reveal the changes in Pol II occupancy in the absence of Cmr1. The WT and mutant strains were grown in Synthetic complete and cells were indcued for Gcn4 by treating with Sulfometuron methyl for 30 minutes and processed for chromatin immunoprecipitation using antibodies against Myc and Rpb3 (subunit of Pol II).
Project description:Our structural and biochemical studies show that S. cerevisiae RNA Polymerase II (RNAPII) homodimerizes through the stalk domain (formed by the Rpb4-Rpb7 subunits). To explore the biological impact of disrupting this interaction we introduced a triple point mutation at the RNAPII dimerization interface in Rpb7 (Q96A, H97A, F109K). To test the impact of the dimerziation mutant on RNAPII occupancy, we performed ChIP-seq using a monoclonal antibody against the Rpb3 subunit (1Y26, abcam) of RNAPII, in WT and Rpb7-QHF cells.
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.