Project description:Estrogen Receptor alpha (ERα) is a key driver of most breast cancers, and it is the target of endocrine therapies used in the clinic to treat women with ERα positive (ER+) breast cancer. The two methods ChIP-seq (chromatin immunoprecipitation coupled with deep sequencing) and RIME (Rapid Immunoprecipitation of Endogenous Proteins) have greatly improved our understanding of ERα function during breast cancer progression and in response to anti-estrogens. A critical component of both ChIP-seq and RIME protocols is the antibody that is used to pull down the bait protein. To date, most of the ChIP-seq and RIME experiments for the study of ERα have been performed using the sc-543 antibody from Santa Cruz Biotechnology. However, this antibody has been discontinued, thereby severely impacting the study of ERα in normal physiology as well as diseases such as breast cancer and ovarian cancer. Here, we compare the sc-543 antibody with other commercially available antibodies, and we show that 06-935 (EMD Millipore) and ab3575 (Abcam) antibodies can successfully replace the sc-543 antibody for ChIP-seq and RIME experiments.
Project description:Meiotic chromosome architecture called M-bM-^@M-^\axis-loop structuresM-bM-^@M-^] and histone modifications have been demonstrated to regulate the Spo11-dependent formation of DNA double-strand breaks (DSBs) that trigger meiotic recombination. Using genome-wide chromatin immunoprecipitation (ChIP) analyses followed by deep sequencing, we compared the genome-wide distribution of the axis protein Rec8 (the kleisin subunit of meiotic cohesin) with that of oligomeric DNA covalently bound to Spo11, indicative of DSB sites. The frequency of DSB sites is overall constant between Rec8 binding sites. However, DSB cold spots are observed in regions spanning M-BM-10.8 kb around Rec8 binding sites. The axis-associated cold spots are not due to exclusion of Spo11 localization from the axis, since ChIP experiments revealed that substantial Spo11 persists at Rec8 binding sites during DSB formation. Spo11 fused with Gal4 DNA binding domain (Gal4BD-Spo11) tethered in close proximity (M-bM-^IM-$0.8 kb) to Rec8 binding sites hardly forms meiotic DSBs, in contrast with other regions. In addition, H3K4 tri-methylation (H3K4me3) remarkably decreases at Rec8 binding sites. These results suggest that reduced histone H3K4me3 in combination with inactivation of Spo11 activity on the axis discourages DSB hot spot formation. ChIP-seq analyses of Rec8, Spo11, and Gal4BD-Spo11 on budding yeast meiotic chromosomes M-bM-^@M-" Distribution of Rec8 in wt and Gal4BD-Spo11-expressing cells at 4h after meiotic induction M-bM-^@M-" Distribution of Spo11 at 3h, 4h, and 5h after meiotic induction M-bM-^@M-" Distribution of Gal4BD-Spo11 at 0h after meiotic induction
Project description:whole genome analysis of RNA pol II and histone H3 in WT and Spt6-depleted cells using a tetracycline regulated ts degron mutant, spt6-td. ChIP-seq of histone H3and pol II in budding yeast (W303 background)
Project description:Asf1, through its histone chaperone activity, helps chromatin closing/opening during DNA replication, repair, recombination and transcription. Despite extensive research on Asf1-mediated physiological functions, a genome-wide localization map is lacking, limiting our knowledge of chromosomal features targeted by Asf1. We present a high-resolution genome-wide map of Asf1, localizing at essentially all pol III-transcribed genes, highly active pol II-transcribed genes and heterochromatic features. Pol III-transcribed genes are negatively regulated by Asf1, whereas pol II genes are regulated indirectly by Asf1-dependent H3K56 acetylation. Interestingly, Asf1 localization along yeast chromosomes shows nearly identical distribution to that of the condensin complex, predicting a functional overlap in chromosome architecture and genome organization. ChIP-seq analysis of Asf1 targets using a yeast strain that expresses an 18-Myc tag fused to the C-terminus of ASF1. Two biological replicates and one mock/control were performed. The Illumina GAII was used. ChIP-seq reads are aligned to the budding yeast sacCer3 (2011) assembly.
Project description:The Scc2/Scc4 complex binds to broad nucleosome-free regions in the promoters of highly expressed genes. The cohesin loader is recruited to these sites by the RSC chromatin remodeling complex ChIp- Sequencing analysis of the distribution of Scc2 and Scc4 on budding yeast chromosomes.An input sample was analysed as a control.
Project description:Determining the genomic localization of chromatin features is an essential aspect of investigating gene expression control, and ChIP-Seq has long been the gold standard technique for interrogating chromatin landscapes. Recently, the development of alternative methods, such as CUT&Tag, have provided researchers with alternative strategies that eliminate the need for chromatin purification, and allow for in situ investigation of histone modifications and chromatin bound factors. Mindful of technical differences, we set out to investigate whether distinct chromatin modifications were equally compatible with these different chromatin interrogation techniques. We found that ChIP-Seq and CUT&Tag performed similarly for modifications known to reside at gene regulatory regions, such as promoters and enhancers, but major differences were observed when we assessed enrichment over heterochromatin-associated loci. Unlike ChIP-Seq, CUT&Tag detects robust levels of H3K9me3 at a substantial number of repetitive elements, with especially high sensitivity over evolutionarily young retrotransposons. IAPEz-int elements for example, exhibited underrepresentation in mouse ChIP-Seq datasets but strong enrichment using CUT&Tag. Additionally, we identified several euchromatin-associated proteins that co-purify with repetitive loci and are similarly depleted when applying ChIP-based methods. This study reveals that our current knowledge of chromatin states across the heterochromatin portions of the mammalian genome is extensively incomplete, largely due to36 limitations of ChIP-Seq. We also demonstrate that newer in situ chromatin fragmentation-based techniques, such as CUT&Tag and CUT&RUN, are more suitable for studying chromatin modifications over repetitive elements and retrotransposons.
Project description:We report the application of ChIP-sequencing technology for high-throughput profiling of histone modifications in budding yeast. By obtaining over four billion bases of sequence from chromatin immunoprecipitated DNA, we generated genome-wide maps of Set1 and H3K4me3 in yeast cells. We find that Set1 and H3 lysine 4 trimethylation locate primarily in open reading frame of genes. In addition, we focus on the distribution of Set1 and H3K4me3 in histone gene clusters and found strong similar binding of Set1 and H3K4me3 on all histone genes.