Project description:We report the genomic localization of cohesin oligomers in nocodazole arrested yeast cells. Two alleles of SMC3 were expressed in yeast cells, one fused to BirA enzyme and the other tagged with AviTag. Cohesin oligomers were biotinylated and ChIP with streptavidin beads. As control experiments, cohesin localization on chromosome was determined in strains expresses freely diffusable BirA enzyme, where all Smc3 proteins were biotinylated; non-specific ChIP were determined in strains with no BirA.
Project description:genomic localization of the budding yeast cohesin complex was mapped in mitotically arrested cells by Mcd1 ChIP followed by hybridization to high-density tiled microarrays Cells were synchronized first in G1 and then released into media containing the microtubule poison nocodazole. Cells were fixed and processed for ChIP once arrested as large-budded cells. Immunoprecipitated DNA and total genomic DNA not subjected to immunoprecipitation were competitively hybridized to Nimblegen whole genome arrays.
Project description:genomic localization of the budding yeast cohesin complex was mapped in mitotically arrested cells by Mcd1 ChIP followed by hybridization to high-density tiled microarrays
Project description:Purpose: The Goal of this study is to look at 1) Differences in genome wide localization of Scc2 between wild type and scc4-m35 cells in S-phase 2) Differences in genome wide localisation of Scc1 cohesin between wild type and scc4-m35 in metaphase arrested cells. Method: 1) Wild-type (AM15307) and scc4-m35 (AM15311) cells carrying SCC2-3FLAG were fixed for 2 hr, 15 min following an a-factor arrest. Samples were harvested, anti-HA ChIP was performed and both input and IP samples were sequenced for both strains. 2) Wild-type (AM1145), wild type constructed in the same way as the mutant strain (carrying a HIS3 marker) (AM15540) and scc4-m35 mutant (AM15537) cells carrying SCC1-6HA were synchronised with a-factor and arrested in mitosis by treatment with nocodazole/benomyl for 2 hr. Samples were harvested, anti-HA ChIP was performed and input and IP samples were sequenced for the three strains. Results: 1) This experiment did not yield meaningful data. 2) All 16 centromeres were specifically depleted of Scc1 in the scc4-m35 background. Scc1 depletion extended roughly 10 kilobases to either side of the core centromere but not to chromosome arms 1) ChIP-seq for S. cerevisiae Scc2-3FLAG in S-phase cells in Wild type and in scc4-m35 mutant (samples VM1-VM4). 2) ChIP-seq for Scc1-6HA in metaphase-arrested cells in Wild type and in scc4-m35 mutant (samples VM5-VM10) Vasso Makrantoni: experiments and Alastair Kerr: ChIP Seq Data analysis https://github.com/AlastairKerr/Hinshaw2015
Project description:Purpose: The goal of this study is to look at differences in genome wide localisation of Scc1 cohesin between wild type and scc4-m35 in metaphase arrested cells. Method: Wild-type (AM1145), wild type constructed in the same way as the mutant strain (carrying a HIS3 marker) (AM15540) and scc4-m35 mutant (AM15537) cells carrying SCC1-6HA were synchronised with a-factor and arrested in mitosis by treatment with nocodazole/benomyl for 2 hr. Samples were harvested, anti-HA ChIP was performed and input and IP samples were sequenced for the three strains. Results: All 16 centromeres were specifically depleted of Scc1 in the scc4-m35 background. Scc1 depletion extended roughly 10 kilobases to either side of the core centromere but not to chromosome arms
Project description:The 3D architecture that the genome is folded into is regulated by CTCF, which determines domain borders, and cohesin, which generates interactions within domains. However, organisms lacking CTCF have been reported to still have cohesin-mediated 3D structures with strong borders. How this can be achieved and precisely regulated are yet unknown. Using in situ Hi-C, we found that 3’-end RNA processing factors coupled with proper transcription termination are a cis-acting determinant that regulates the localization and dynamics of cohesin on the chromosome arms. Loss of RNA processing factors, including nuclear exosome and Pfs2, destabilizes cohesin from the 3'-ends of convergent genes and results in decreased cohesin-mediated domain boundaries. We observed the co-localization between Rad21 and a wide range of 3'end RNA processing/termination factors. Further, deletion of Rrp6 leads to cohesin redistribution to facultative heterochromatin, resulting in improper domain boundaries. Importantly, we observed that knockdown of Rrp6Exosc10 caused a defect in cohesin binding and loss of local topologically associating domains (TADs) interactions in mouse embryonic stem cells. Based on these findings, we propose a novel function of the RNA surveillance pathway in 3D genome organization via cohesin complex, which provides the molecular basis underlying the dynamics of cohesin function.
Project description:In addition to its well-know function in chromosome segregation, increasing evidence implicates cohesin in the control of gene expression. It has been previously reported that inactivation of the cohesin loader Mis4 in G1-arrested cells leads to the dissociation of cohesin from chromatin. We exploited this experimental situation to ask whether this loss of cohesin would affect gene expression on a genome-wide scale. Three independent inoculates (biological replicates) of cells carrying either the thermosensitive mis4-367 or the wild-type mis4+ allele were grown at permissive temperature of 25C. Cells were G1-arrested by titrating out the Cdc10 transcription factor by overexpression of the C-terminal fragment of its binding partner Res1, and then shifted for 2 hours at 37C. Cells were harvested before and after the temperature shift to proceed to total RNA extraction.
Project description:Purpose: Cohesin is an important structural regulator of the genome. Whether cohesin HEAT repeat accessory proteins PDS5A and PDS5B differentially contribute to cohesin function remains unclear. The purpose of this study is to interrogate how PDS5A and PDS5B affect cohesin localization and gene expression in mouse embronic stem cells (mESCs) Method: Genome wide binding patterns of PDS5A, PDS5B, and cohesin in wildtype cells as well as in PDS5 CRISPR/Cas9 genome edited knockout cells were assessed via chromatin immunoprecipitation followed by high throughput sequencing (ChIP-seq). The redundancy of the PDS5 subunits was addressed by using siRNA against PDS5B in a PDS5A-knockout background.
Project description:During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Diminished Smc5/6 function causes severe defects in nuclear division, but the underlying causes of these defects remain unclear. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of joint-molecule intermediates. Furthermore, we find that Smc5/6 specifically promotes resolution of joint molecules via the XPF-family endonuclease, Mus81-Mms4Eme1. We propose that Smc5/6 acts as a chaperone for M-bM-^@M-^XmitoticM-bM-^@M-^Y-like recombination processes during meiosis. ChIP-chip was used to compare Smc5 localization in wild-type and spo11 strains
Project description:Purpose: Cohesin is a ring-shaped complex that is critical to genome organization and is an important regulator of gene expression. How cohesin accessory proteins contribute to cohesin function remains unclear. The purpose of this study is to assess the roles of cohesin accessory proteins, STAG1 and STAG2, in cohesin localization and gene expression. Method: Genome wide binding patterns of the STAGs and cohesin in wildtype cells as well as in STAG CRISPR/Cas9 genome edited knockout cells were assessed via chromatin immunoprecipitation followed by high throughput sequencing (ChIP-seq). The redundancy of the STAGs was addressed by using siRNA against STAG1 in a STAG2-knockout background.