Project description:The Tip60 (also known as Kat5) lysine acetyltransferase functions broadly as a transcriptional co-activator that acetylates histones. In contrast, Tip60 functions in embryonic stem cells (ESCs) both to silence genes that promote differentiation and to activate genes required for proliferation. The mechanism by which Tip60 functions as a repressor is unknown. Here we show that the class II histone deacetylase Hdac6 co-purifies with Tip60-p400 complex from ESCs and is necessary for complete silencing of most differentiation genes targeted by Tip60. In contrast to differentiated cells, where Hdac6 is mainly cytoplasmic and does not interact with Tip60, Hdac6 is largely nuclear in ESCs and neural stem cells (NSCs) and interacts with Tip60-p400 in both cell types. Hdac6 is enriched at promoters bound by Tip60-p400 in ESCs, but while Tip60 binds on both sides of transcription start sites (TSSs), Hdac6 binding overlaps with only the downstream Tip60 peak. Surprisingly, Hdac6 does not deacetylate histones at these sites, but rather is required for Tip60 binding. These data suggest that nuclear exclusion of Hdac6 during differentiation plays a major role in modulation of Tip60-p400 function. We determined the genome-wide localization of Tip60 and Hdac6 in mouse ES cells, and examined genomic binding profiles of Tip60 and Hdac6 upon indicated knockdown by ChIP-seq. We examined genomic binding profiles of p400 upon indicated knockdown by ChIP-seq.
Project description:Ptch1 is a critical negative feedback regulator of the Hedgehog signaling and is upregulated in response to pathway activation. How tissue specific responses are mediated remains unknown. Here, we performed ChIP-seq analysis for epitope-tagged endogenous Gli3 protein to identify limb-specific binding regions within the 500 kb region surrounding Ptch1. ChIP was carried out using an endogenously FLAG-tagged Gli3 protein.
Project description:In the vertebrate neural tube, regional Sonic hedgehog (Shh) signaling invokes a time- and concentration-dependent induction of six different cell populations mediated through Gli transcriptional regulators. Elsewhere in the embryo, Shh/Gli responses invoke different tissue appropriate regulatory programs. To elucidate Shh/Gli regulation of neural fate sepcification, we performed Gli1 ChIP-Seq analysis. We further analyzed two transcription factors whose motifs were enriched in Gli1 ChIP data (Sox2 and Foxa2). Two active histone marks (H3K4me2 and H3K27ac) were additionally analyzed to study activity status of Shh-responsive cis-elements. Active enhancer histone marks and transcription factor binding patterns were obtained from neuralized emrbyoid bodies. Biological replicates were performed for Gli1 and mock FLAG chips. Histone profiling for enhancer marks were taken from time course experiment performed in parallel.
Project description:Eukaryotic RNA polymerase II (Pol II) has evolved an array of heptad repeats with the consensus sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7 at the carboxy-terminal domain (CTD) of the large subunit (Rpb1). Differential phosphorylation of Ser2, Ser5, and Ser7 in the 5M-bM-^@M-^Y and 3M-bM-^@M-^Y regions of genes coordinates the binding of transcription and RNA processing factors to the initiating and elongating polymerase complexes. Here, we report phosphorylation of Thr4 by Polo-like-kinase-3 in mammalian cells. ChIPseq analyses indicate an increase of Thr4-P levels in the 3M-bM-^@M-^Y region of genes occurring subsequently to an increase of Ser2-P levels. A Thr4/Ala mutant of Pol II displays a lethal phenotype. This mutant reveals a global defect in RNA elongation, while initiation is largely unaffected. Since Thr4 replacement mutants are viable in yeast we conclude that this amino acid has evolved an essential function(s) in the CTD of Pol II for gene transcription in mammalian cells. In this study, we investigated the function and ChIPseq genome-wide profiling of Thr4P residue (using the 6D7 antibody) of the Pol II CTD in Raji human B cells in comparison with either total Pol II profiling (N20 antibody, santa-cruz sc-899x), Ser5P CTD (3E8) or Ser2P (3E10) profiling in WT Raji cells. In another set of experiments, we also analysed total Pol II profiling (using an HA tag at the N-terminus of RPB1 and HA antibody Abcam ab9110) when endogenous enzyme is shut down by alpha-amanitin and replaced by either a recominant Pol II with 48 consensus repeats of the CTD (con48) or a mutated version where Thr4 residues were replaced by Ala (Thr4-Ala).In total 6 experimental sets (Pol IIt, Ser5P, Ser2P, Thr4P, con48, Thr4-Ala) were generated for our analysis and for each a biological replicate was performed. Biological replicates were merged when the data showed comparable signal noise ratio. Otherwise a unique replicate, showing the best noise ratio, was chosen for further analysis although the second replicate (for Ser2P and Thr4-Ala experiments). An input control (genomic DNA extracted after reverse crosslinking of the nuclear chip extracts) was performred and used for substraction to the ChIP experiments. One specific input material was used for wt cells, one for con48 and one for Thr4-Ala. Our data were processed to generate final wig files using our in house analysis pipeline essentially as described in Koch et al, (2011) NSMB 18 (8) p956.In brief, after alignment, sequence tags are: (i) artefact removed, (ii) elongated to an in silico optimized actual size of the initial fragments , (iii) input substracted, (iv) merged if applicable, (v) scaled for all experiments to correct for variation of tag number in between experiments. Several of the raw data files were no longer available.
Project description:Several lines of recent evidence support a role for chromatin in splicing regulation. Here we show that splicing can also contribute to histone modification, which implies a bidirectional communication between epigenetics and RNA processing. Genome-wide analysis of histone methylation in human cell lines and mouse primary T cells reveals that intron-containing genes are preferentially marked with H3K36me3 relative to intronless genes. In intron-containing genes, H3K36me3 marking is proportional to transcriptional activity, whereas in intronless genes H3K36me3 is always detected at much lower levels. Furthermore, splicing inhibition impairs recruitment of H3K36 methyltransferase HYPB/Setd2 and reduces H3K36me3, whereas splicing activation has the opposite effect. Moreover, the increase of H3K36me3 correlates with the length of the first intron, consistent with the view that splicing enhances H3 methylation. We propose that splicing is mechanistically coupled to recruitment of HYPB/Setd2 to elongating RNA Polymerase II. This experiment proposes to profile genome-wide binding profiles by ChIP-seq (Illumina, 36 bp tags) of RNA polymerase II (one biological replicate), the histone modification H3K36me3 (2 replicates) and a reference control input sample (genomic DNA after reverse cross-link, one replicate) in a human H1299 lung carcinoma cell line *** Raw data not provided for Samples GSM766322-GSM766324.
Project description:Recent studies have revealed a myriad of non-coding transcripts in different organisms. For instances, the presence of short bidirectional transcripts is a hallmark of active promoters in mammals, while upstream non-coding transcripts can be detected at most expressed genes in conditions where the RNA degradation machinery is inhibited. Here, we used RNA-seq with very high sequencing depth to characterize strand specific transcripts from primary mouse tissues. We found that a substantial fraction of gene promoters sustain expression of long non-coding antisense transcripts. These transcripts have an average size of 6 kb, have features of mature transcripts, but remain associated with the chromatin. We named this new class of non-coding RNAs Long Upstream Antisense Transcripts (LUAT). Strikingly, the LUAT and coding gene pairs are usually co-regulated, with the associated genes often/generally coding for transcriptional regulators functioning during development and cell differentiation. Indeed, these bidirectional promoters share several characteristic of developmental gene promoters, including large CpG islands and high degree of conservation, and display symetrical GC skews. Finally, we found that bidirectional promoters have enlarged platforms of Pol II initiation, associated with an intensified rate of early transcriptional elongation. We concluded that promoters of developmental regulators are characterized by a specialized mechanism of Pol II transcription, whereby Pol II poising is directly coupled to relaxed bidirectional transcription. H3K79me2 ChIP in CD4+,CD8+ double positive thymocytes from C57BL/6 mice was studied, using Illumina sequencer
Project description:This SuperSeries is composed of the following subset Series: GSE38158: mes-2, mes-4 or mes-2; mes-4 mutants vs. wild type GSE38159: Strome MES-4, H3K36me3 and H3K27me3 in mes-4 RNAi EEMB GSE38180: Strome Mes-4, H3K36me3 and H3K27me3 in N2 EEMB Refer to individual Series
Project description:CD8 T cells (TCs) expressing active STAT5 (STAT5CA) transcription factors were found to be superior to un-manipulated counterparts in their long-term persistence, capacity to infiltrate a tumor, thrive in its microenvironment and induce its regression. STAT5CA induced sustained expression of genes controlling tissue homing, cytolytic granule composition, Tc-1-associated effector molecules (GranzymeB+/IFNg+/TNFa+/CCL3+ but IL-2-) and potential for secondary responses. Sustained expression of both T-Bet and Eomes transcription factors was correlated with STAT5 binding to their corresponding genes by ChIPSeq analyses. Additionally, STAT5CA-expressing CD8 TCs demonstrated reduced IL-6R/TGFbRII expression and dampened IL-6 and TGFb1 signaling. Altogether, concerted STAT5/T-Bet/Eomes regulation controls homing, recall responses and resistance to Tc-17 polarization in CD8 TCs. TCRP1A CD8 T lymphocytes were activated by their cognate P1A Ag. After 24h, an active form of Stat5 (STAT5CA) was introduced in activated cells. Culture was continued for another 48h to induce their differentiation in effector T cells. These activated T cells were injected in congeneic hosts and recovered 70 days later from hosts' spleen and lymph nodes: TCRP1A eTC-STAT5CA.