Project description:ChIP-on chip assays to measure the change in histone H3 K36 trimethylation over the yeast genome in wild-type yeast strains. Two color experiment.WT cells. Biological replicates=3 per IP per cell type.
Project description:ChIP-chip assays to measure the occupancy of histone H3 K36me3 over the yeast genome in wildtype, isw1 and chd1 yeast strains. ChIPs were done with K36me3 antibody (Ab 9050) in G1 arrested yeast cells.
Project description:In this study, we measured histone H3Lys4 trimethylation in budding yeast S. cerevisiae for wild type and cnc1Djhd2D yeast mutants. These experiments were performed for yeast cultured to mid-logarithmic phase in non-fermentable carbon.
Project description:The stimulation of trimethylation of histone H3 lysine 4 (H3K4) by H2B monoubiquitination (H2Bub) has been widely studied with multiple mechanisms proposed for this form of histone crosstalk. Cps35/Swd2 within COMPASS is considered to bridge these processes. However, a truncated form of Set1 (762-Set1) is reported to function in H3K4 trimethylation without interacting with Cps35/Swd2, and such crosstalk is attributed to the n-SET domain of Set1 and its interaction with the Cps40/Spp1 subunit of COMPASS. Here, we use biochemical, structural, in vivo, and ChIP-seq approaches to demonstrate that Cps40/Spp1 and the n-SET domain of Set1 are required for the stability of Set1 and not the crosstalk. Furthermore, the apparent wild-type levels of H3K4 trimethylation (H3K4me3) in the 762-Set1 strain is due to rogue methylase activity of this mutant resulting in the mislocalization of H3K4me3 from the promoter-proximal regions to gene bodies and intergenic regions. We have also performed detailed screens and identified yeast strains lacking H2Bub, but containing intact H2Bub enzymes, that have normal levels of H3K4me3, suggesting that ubiquitination may not directly stimulate COMPASS, but rather works in a context of the PAF and Rad6/Bre1 complexes. Our study demonstrates that the ubiquitination machinery and Cps35/Swd2 function to focus COMPASS’ H3K4me3 activity at promoter-proximal regions in a context dependent manner. ChIP-Seq for H3K4ME3 in S. cerevisie wild-type strains and strains expressing a truncated form of Set1: aa762-1080 Set1. H3K4ME3 ChIP-Seq was also compared for wild-type, leo1 knockout, and chd1 knockout strains
Project description:Histone modifications are associated with meiotic recombination hotspots, discrete sites with augmented recombination frequency. For example, trimethylation of histone H3 lysine4 (H3K4me3) marks most hotspots in budding yeast and mouse. Modified histones are known to regulate meiotic recombination partly by promoting DNA double strand break (DSB) formation, but the role and precise landscape of histone modifications at hotspots remain unclear. Here, we studied hotspot-associated modifications in fission yeast and found general features: acetylation of H3 lysine9 (H3K9ac) is strikingly elevated, and H3K4me3 is not significantly enriched. Remarkably, elimination of H3K9ac reduced binding of the DSB-inducing enzyme Rec12 and DSB at hotspots. We also found that the H3K4 metyltransferase Set1 promotes DSB formation at some loci, but it restricts Rec12 binding to hotspots. These results suggest that H3K9ac rather than H3K4me3 is a hotspot-associated mark involved in meiotic DSB formation in fission yeast. S.pombe cells in a pat1-114 background were induced to enter meiosis by the haploid meiosis system, and harvested one hour after the induction. ChIP were performed using anti-H3Cter, H3K9ac, -H3K14ac and -H3K4me3 antibodies. pat1-114 rad50S rec12+-FLAG cells in a wild type, H3K9A or set1+ deletion background were induced to enter meiosis by the haploid meiosis system, and harvested five hours after the induction. ChIP were performed using anti-FLAG antibodies.
Project description:The stimulation of trimethylation of histone H3 lysine 4 (H3K4) by H2B monoubiquitination (H2Bub) has been widely studied with multiple mechanisms proposed for this form of histone crosstalk. Cps35/Swd2 within COMPASS is considered to bridge these processes. However, a truncated form of Set1 (762-Set1) is reported to function in H3K4 trimethylation without interacting with Cps35/Swd2, and such crosstalk is attributed to the n-SET domain of Set1 and its interaction with the Cps40/Spp1 subunit of COMPASS. Here, we use biochemical, structural, in vivo, and ChIP-seq approaches to demonstrate that Cps40/Spp1 and the n-SET domain of Set1 are required for the stability of Set1 and not the crosstalk. Furthermore, the apparent wild-type levels of H3K4 trimethylation (H3K4me3) in the 762-Set1 strain is due to rogue methylase activity of this mutant resulting in the mislocalization of H3K4me3 from the promoter-proximal regions to gene bodies and intergenic regions. We have also performed detailed screens and identified yeast strains lacking H2Bub, but containing intact H2Bub enzymes, that have normal levels of H3K4me3, suggesting that ubiquitination may not directly stimulate COMPASS, but rather works in a context of the PAF and Rad6/Bre1 complexes. Our study demonstrates that the ubiquitination machinery and Cps35/Swd2 function to focus COMPASS’ H3K4me3 activity at promoter-proximal regions in a context dependent manner.
Project description:Histone modifications are associated with meiotic recombination hotspots, discrete sites with augmented recombination frequency. For example, trimethylation of histone H3 lysine4 (H3K4me3) marks most hotspots in budding yeast and mouse. Modified histones are known to regulate meiotic recombination partly by promoting DNA double strand break (DSB) formation, but the role and precise landscape of histone modifications at hotspots remain unclear. Here, we studied hotspot-associated modifications in fission yeast and found general features: acetylation of H3 lysine9 (H3K9ac) is strikingly elevated, and H3K4me3 is not significantly enriched. Remarkably, elimination of H3K9ac reduced binding of the DSB-inducing enzyme Rec12 and DSB at hotspots. We also found that the H3K4 metyltransferase Set1 promotes DSB formation at some loci, but it restricts Rec12 binding to hotspots. These results suggest that H3K9ac rather than H3K4me3 is a hotspot-associated mark involved in meiotic DSB formation in fission yeast.
Project description:ChIP-chip assays to measure the occupancy of histone H3 K36me3 over the yeast genome in wildtype, isw1 and chd1 yeast strains. ChIPs were done with K36me3 antibody (Ab 9050) in G1 arrested yeast cells. Two color experiment. Biological replicates=3 per IP per cell type.
Project description:ChIP-on-chip analysis of histone H3 and histone H3 lysine 4 trimethylation in cells induced to undergo synchronous meiosis after growth in nitrogen-rich conditions or after nitrogen depletion.
Project description:ChIP-on-chip analysis of histone H3 and histone H3 lysine 4 trimethylation in cells induced to undergo synchronous meiosis after growth in nitrogen-rich conditions or after nitrogen depletion. Comparison of H3 and H3k4Me3 in diploid pat1-114 cells grown in -N and +N conditions.