CDK8 ChIP-seq from HCT116 cells in normoxia and hypoxia
Ontology highlight
ABSTRACT: To test if CDK8 acts directly at HIF1A target genes, we performed ChIP-seq experiments in HCT116 cells under normoxic and hypoxic conditions. ChIP-seq for CDK8 versus Input under normoxia and 24hrs hypoxia (1% O2).
Project description:Cellular differentiation requires cells to undergo dramatic but strictly controlled changes in chromatin organization, transcriptional regulation, and protein production and interaction. To understand the regulatory connections between these processes, we applied a multi-omics approach integrating proteomic, transcriptomic, chromatin accessibility, protein occupancy, and protein-chromatin interaction data acquired during differentiation of mouse embryonic stem cells (ESCs) into post-mitotic neurons. We found extensive remodeling of the chromatin that was preceding changes on RNA and protein levels. We found the pluripotency factor Sox2 as regulator of neuron-specific genes and, as a potential mechanism, revealed its genomic redistribution from pluripotency enhancers to neuronal promoters and concomitant change of its protein interaction network upon differentiation. We identified Atrx as a major Sox2 partner in neurons, whose co-localisation correlated with an increase in active enhancer marks and increased expression of nearby genes, and where deletion of a Sox2-Atrx co-bound site resulted in reduced expression of the proximal gene. Collectively, these findings provide key insights into the regulatory transformation of Sox2 during neuronal differentiation and highlight the significance of multi-omic approaches in understanding gene regulation in complex systems.
Project description:The model describing that aberrant CpG island (CGI) methylation leads to transcription repression of tumor suppressor genes and thereby is implicated in tumor progression has been established in many cancers. However, recent studies indicated aberrantly hypermethylated genes in multiple cancers are already repressed in pre-cancerous tissues despite their promoters are hypomethylated. Here, we hypothesized that the occurrence of CGI promoter hypermethylation in cancers are associated with Polycomb-repressive complex and the associated H3K27me3 mark in pre-cancerous tissues. By using a ChIP-BS-seq technology that examines methylation of the DNA fragments precipitated by the antibodies to histone modifications, we provided direct evidences showing that genes highly enriched with H3K27me3 marks both in cancer and normal cells became aberrantly hypermethylated in CGI promoters in cancer cells in comparison with normal cells. Furthermore, we confirmed that these genes consistently were significantly hypermethylated in TCGA primary cancer in comparison with normal tissues. Thus, we provided direct evidences supporting that the presence of H3K27m3 may serve as a guide to promoter hypermethylation. This will spur future work on epigenetic signature of combined histone and DNA methylation that could define a cancerM-bM-^@M-^Ys epigenetic abnormalities, therefore helping distinguish subtypes of cancers and aiding future diagnosis and therapeutics of cancers. We applied ChIP-BS technology to examine H3K27me3 marks, which are catalyzed by the SET domain histone methyltransferase EZH2 and have a repressive function with 50bp pair-end sequencing. found H3K27me3 marks were enriched preferentially at CpG islands, (+/-500) transcription start sites (TSSs) and exons in two GC cell lines (BGC-823 and AGS). In YH cells, H3K27me3 marks were only preferentially enriched at CpG islands. In contrast, Hela cells presented a reverse pattern with highest H3K27me3 enrichment in intergenic regions. To confirm this result in Hela cells, we performed two independent replicates of ChIP-Seq and ChIP-BS-seq. Cause of useful was relative small. we still sequenced one 100bp pe reads replicate for H3K4me3 and two replicate for H3K27me3 ChIP-BS-seq.
Project description:Chromatin immunoprecipitation (ChIP) has been a cornerstone for epigenetic analyses over the last decades, but even coupled to sequencing approaches (ChIP-seq), it is ultimately limited to one protein at a time. In a complementary effort, we here combined ChIP with label-free quantitative (LFQ) mass spectrometry (ChIP-MS) to interrogate local chromatin compositions. We demonstrate the versality of our approach at telomeres, with transcription factors, in tissue and by dCas9-driven locus-specific enrichment.
Project description:Human embryonic stem cells (hESCs) are a powerful tool for modeling regenerative therapy. To search for the genes that promote hematopoietic development from human pluripotent stem cell, we overexpressed a list of hematopoietic regulator genes in human pluripotent stem cell-derived CD34+CD43- endothelial cells (ECs) enriched in hemogenic endothelium. Among genes tested, only SOX17, a gene encoding a transcription factor of the SOX family, promoted cell growth and supported expansion of CD34+CD43+CD45-/low cells expressing a hemogenic endothelial maker VE-cadherin. SOX17 was highly expressed in CD34+CD43- ECs but at a low level in CD34+CD43+CD45- pre-hematopoietic progenitor cells (pre-HPCs) and CD34+CD43+CD45+ HPCs. SOX17-overexpressing cells formed sphere-like colonies and generated few hematopoietic progenies. However, they retained hemogenic potential and gave rise to hematopoietic progenies upon inactivation of SOX17. Global gene expression analyses revealed that the CD34+CD43+CD45-/low cells expanded upon overexpression of SOX17 are hemogenic endothelium-like cells developmentally placed between ECs and pre-HPCs. Of interest, SOX17 also reprogrammed both pre-HPCs and HPCs into hemogenic endothelium-like cells. Genome-wide mapping of SOX17 revealed that SOX17 directly activates transcription of key regulator genes for vasculogenesis, hematopoiesis, and erythrocyte differentiation. Depletion of SOX17 in CD34+CD43- ECs severely compromised their hemogenic activity. These findings suggest that SOX17 plays a critical role in priming hemogenic potential in ECs, thereby regulates hematopoietic development from hESCs. This SuperSeries is composed of the SubSeries listed below. ChIP on chip analysis was carried out using the Mouse Promoter ChIP-on-chip Microarray Set (G4490A, Agilent, Palo Alto, Calif., USA). MEFs were subjected to ChIP assay using a Ring1B antibody. Purified immunoprecipitated and input DNA was subjected to T7 RNA polymerase-based amplification. Labeling, hybridization and washing were carried out according to the Agilent mammalian ChIP-on-chip protocol (ver.9.0). Scanned images were quantified with Agilent Feature Extraction software under standard conditions. Human ES cells were differentiated for 6 days in EBs, then CD34+CD43-CD45- endothelial cells were isolated, plated onto OP9 cells, and transduced with the 4OH-tamoxifen (4OHT)-inducible 3M-CM-^WFLAG-tagged Sox17-ERT retrovirus. The cells were seeded on OP9 stromal cells and cultured in the presence of 4OH-tamoxifen. At day 27 of the co-culture with OP9 cells, CD34+CD43+CD45low hemogenic endothelium-like cells overexpressing Sox17-ERT were collected by CD34 magnetic-activated cell sorting (MACS) and subjected to a ChIP-chip analysis. ChIP on chip analysis was carried out using the Mouse Promoter ChIP-on-chip Microarray Set (G4490A, Agilent, Palo Alto, Calif., USA). MEFs were subjected to ChIP assay using a Ring1B antibody. Purified immunoprecipitated and input DNA was subjected to T7 RNA polymerase-based amplification. Labeling, hybridization and washing were carried out according to the Agilent mammalian ChIP-on-chip protocol (ver.9.0). Scanned images were quantified with Agilent Feature Extraction software under standard conditions. Human ES cells were differentiated for 6 days in EBs, then CD34+CD43-CD45- endothelial cells were isolated, plated onto OP9 cells, and transduced with the 4OH-tamoxifen (4OHT)-inducible 3M-CM-^WFLAG-tagged Sox17-ERT retrovirus. The cells were seeded on OP9 stromal cells and cultured in the presence of 4OH-tamoxifen. At day 27 of the co-culture with OP9 cells, CD34+CD43+CD45low hemogenic endothelium-like cells overexpressing Sox17-ERT were collected by CD34 magnetic-activated cell sorting (MACS) and subjected to a ChIP-chip analysis.
Project description:In mammalian cells, the Myc oncoprotein binds to thousands of promoters. During mitogenic stimulation of primary lymphocytes, Myc promotes an increase in expression of virtually all genes. In contrast, Myc-driven tumour cells differ from normal cells in expression of specific sets of up- and downregulated genes that have significant prognostic value. To understand this discrepancy, we studied the consequences of inducible expression and depletion of Myc in human cells and murine tumour models. Changes in Myc levels activate and repress specific sets of direct target genes that are characteristic of Myc-transformed tumour cells. Three factors account for this specificity: First, the magnitude of response parallels the change in occupancy by Myc at each promoter. Functionally distinct classes of target genes differ in the E-box sequence bound by Myc, arguing that different cellular responses to physiological and oncogenic Myc levels are controlled by promoter affinity. Secondly, Myc both positively and negatively affects transcription initiation independent of its effect on transcriptional elongation. Third, complex formation with Miz1 mediates repression of multiple target genes by Myc and the ratio of Myc and Miz1 bound to each promoter correlates with the direction of response. Myc, Miz1 and RNA polymerase II ChIPseq as well as RNAseq experiments in two human cancer cell lines and murine carcinoma cells as well as fibroblasts from Miz1M-bM-^HM-^FPOZ mice. All sequencing experiment were performed on an Illumina Genome Analyzer IIx.
Project description:The RAG1 endonuclease, together with its cofactor RAG2, is essential for V(D)J recombination but is a potent threat to genome stability. The sources of RAG1 mistargeting and the mechanisms that have evolved to suppress it are poorly understood. Here, we report the surprising finding that RAG1 binds to thousands of sites in the genome of developing lymphocytes, primarily at active promoters and enhancers. The genome has responded by reducing the abundance of "cryptic" recombination signals near sites of RAG1 binding. This depletion operates specifically on the RSS heptamer, with nonamers enriched at RAG1 binding sites. Reversing this RAG-driven depletion of cleavage sites by insertion of strong recombination signals creates an ectopic hub of RAG-mediated V(D)J recombination and chromosomal translocations. Our findings delineate rules governing RAG binding in the genome, identify areas at risk of RAG-mediated damage, and highlight the evolutionary struggle to accommodate programmed DNA damage in developing lymphocytes. RAG1,RAG2 and H3K4me3 ChIP-seq profiles of human thymocytes, mouse thymocytes and preB cells, and Abelson pre-B cell line treated with STI-571
Project description:Most B cell lymphomas arise in the germinal center (GC), where humoral immune responses evolve from potentially oncogenic cycles of mutation, proliferation, and clonal selection. Although lymphoma gene expression diverges significantly from GC-B cells, underlying mechanisms that alter the activities of corresponding regulatory elements (REs) remain elusive. Here we define the complete pathogenic circuitry of human follicular lymphoma (FL), which activates or decommissions transcriptional circuits from normal GC-B cells and commandeers enhancers from other lineages. Moreover, independent sets of transcription factors, whose expression is deregulated in FL, target commandeered versus decommissioned REs. Our approach reveals two distinct subtypes of low-grade FL, whose pathogenic circuitries resemble GC-B or activated B cells. Remarkably, FL-altered enhancers also are enriched for sequence variants, including somatic mutations, which disrupt transcription factor binding and expression of circuit-linked genes. Thus, the pathogenic regulatory circuitry of FL reveals distinct genetic and epigenetic etiologies for GC-B transformation. Molecular profiling of follicular lymphoma, resting peripheral blood and tonsillar B cells using Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE) and chromatin immunoprecipitation (H3ac and H3K27ac).
Project description:Understanding the precise functions and relationship of BRD2 with other bromodomain and extraterminal motif (BET) proteins is central for the application of BET-specific and pan inhibitors. Here, we used acute protein degradation and quantitative genomic and proteomic approaches to investigate the primary functions of BRD2 in transcription. We report that BRD2 is required for TAF3-mediated Pol II initiation at low levels of H3K4me3-modified promoters and Pol II elongation by suppressing R-loops. Single and double depletion revealed that BRD2 and BRD3, but not BRD4, redundantly and independently function in Pol II transcription at different promoters and cooperatively occupy enhancers. Interestingly, we found that depletion of BRD2 affects the expression of different genes during differentiation processes, priming with promoter regulation in ES cells. Therefore, our results suggest complex interconnections between BRD2 and BRD3 at promoters to fine-tune Pol II initiation and elongation for control of cell state.
Project description:Despite correlations between histone methyltransferase (HMT) activity and gene regulation, direct evidence that HMT activity is responsible for gene activation is sparse. We address the role of the HMT activity for MLL1, a histone H3 lysine 4 (H3K4) methyltransferase critical for maintaining hematopoietic stem cells (HSCs). Here we show that the SET domain and thus HMT activity of MLL1 is dispensable for maintaining HSCs and for supporting leukemogenesis driven by the MLL-AF9 fusion oncoprotein. Upon Mll1 deletion, histone H4 lysine 16 (H4K16) acetylation was selectively depleted at MLL1 target genes in conjunction with reduced transcription. Surprisingly, inhibition of SIRT1 was sufficient to prevent the loss of H4K16 acetylation and the reduction in MLL1 target gene expression. Thus, recruited MOF activity, and not the intrinsic HMT activity of MLL1, is central for the maintenance of HSC target genes. In addition, this work reveals a role for SIRT1 in opposing MLL1 function. 11 Samples, 5 controls and 5 KOs with antibodies H3K4me1, H3K4me3, and H3K27Ac. One input Sample.
Project description:Epigenetic regulators have emerged as critical factors governing the biology of cancer. Here, in the context of melanoma, we show that RNF2 is prognostic, exhibiting progression-correlated expression in human melanocytic neoplasms. Through a series of gain of function and loss of function studies, we establish that RNF2 is oncogenic and pro-metastatic. Mechanistically, RNF2-mediated invasive behavior is dependent on its ability to mono-ubiquitinate H2AK119 at the promoter of LTBP2, resulting in silencing of this negative regulator of TGFβ signaling. In contrast, RNF2's oncogenic activity did not require its catalytic activity nor derives from its canonical gene repression function, rather RNF2 drives proliferation through direct transcriptional up-regulation of the cell cycle regulator CCND2. In summary, RNF2 regulates distinct biological processes in the genesis and progression of melanoma via distinct molecular mechanisms, underscoring the complex and multi-faceted actions of epigenetic regulators in cancer. RNF2 is overexpressed in immortalized human melanocytes HMEL-BRAFV600E to address impact of RNF2 overexpression in melanoma and identify RNF2 target genes. ChIP was performed to identify RNF2 binding sites using antibody against the V5 tag.