Proceedings of the National Academy of Sciences of the United States of America 20181212 52
Molecular subtyping of cancer offers tremendous promise for the optimization of a precision oncology approach to anticancer therapy. Recent advances in pancreatic cancer research uncovered various molecular subtypes with tumors expressing a squamous/basal-like gene expression signature displaying a worse prognosis. Through unbiased epigenome mapping, we identified deltaNp63 as a major driver of a gene signature in pancreatic cancer cell lines, which we report to faithfully represent the highly a ...[more]
Project description:We investigated the regions that are occupied by deltaNp63 in BxPC-3 and L3.6pl and identification of super enhancers in different pancreatic cancer cell lines. Thereby, we identified a group of 45 super enhancers that are associated with poorer prognosis and are highly dependent on deltaNp63.
Project description:We performed ATAC-seq in the GR18 cell line (derived from U2OS ATTC:HTB-96, stably transfected with an expression construct for GR), upon glucocorticoid (dexamethasone) or vehicle (ethanol) treatment for 90 minutes.
Project description:We assessed the genome-wide binding of the histone acetylase MOF and members of its two associated complexes, the male-specific lethal and the non-specific lethal complex (MSL, NSL). We generated ChIP-seq profiles for MOF, MSL1, MSL2, KANSL3, and MCRS1 from mouse embryonic stem cells and neuronal progenitor cells. By using two replicates per sample and stringent filtering criteria, we identify five basic groups of genome regions where the proteins show either mutual or exclusive binding. We find that the NSL complex members (KANSL3, MCRS1) target the TSSs of broadly expressed genes with housekeeping functions in both cell types. MOF and particularly the MSL complex target a subset of these NSL-complex-targets, too. In addition, we find several thousand TSS-distal binding sites, particularly in ESCs, where KANSL3, MSL2 and MCRS1 show strong enrichments for annotated ESC enhancers. The vast majority of the binding to these ESC distal regulatory elements is lost in NPCs. Finally, we identify mostly intronic and intergenic regions with predominant MSL2 enrichments without the presence of its known interactors. These binding sites do not overlap with ESC marks of active chromatin (e.g. DNase hypersensitivity sites), but the they increase in number upon differentiation and we detect a strong signature of the (CAGA)n motif. Our study provides the first comprehensive analysis of MOF in the context of its two complexes in the mouse and reveals shared as well as distinct and dynamic functions for gene regulation and pluripotency. ChIP-seq of MOF and members of its associated complexes (MSL complex: MSL1, MSL2; NSL complex: KANSL3, MCRS1) in male mouse embryonic stem cells and neuronal progenitor cells derived from them.
Project description:Domains of heterochromatin play important roles in the maintenance and regulation of eukaryotic genomes. However, the repressive nature of heterochromatin combined with its propensity to self-propagate necessitates the existence of robust mechanisms that limit heterochromatin spreading and thereby avoid silencing of expressed genes. A number of specific sequence elements have been found to serve as barriers to heterochromatin spreading; however, the mechanisms by which spreading is curtailed are generally not well understood. Here we uncover a role for PAF complex component Leo1 in regulating heterochromatin cis-spreading. A genetic screen revealed that loss of Leo1 results in spreading of heterochromatin across a centromeric (IRC) boundary element in fission yeast. Similar heterochromatin spreading was seen upon deletion of other components of the PAF complex, but not other factors involved in transcription-coupled chromatin modification, indicating a specific role for the PAF complex in heterochromatin regulation. Loss of Leo1 is associated with reduced levels of H4K16 acetylation at the boundary, while tethering of the H4K16 acetyltransferase Mst1 to boundary chromatin suppresses heterochromatin spreading in leo1Δ cells, suggesting that Leo1 antagonises heterochromatin spreading by facilitating H4K16 acetylation. Interestingly, Leo1 also regulates heterochromatin spreading independently of boundaries, and loss of Leo1 causes redistribution of heterochromatin, in particular resulting in substantial expansion of telomeric heterochromatin domains. The PAF complex is known to be an important regulator of transcription-related chromatin modifications; our findings reveal a previously undescribed role for this complex in global regulation of heterochromatin spreading in cis. 8 samples: input (whole cell extract) and IP from H3K9me2 ChIP in wild-type and leo1Δ cells, in duplicate
Project description:Mouse Bcell, upon ectopic expression of the transcription factor Cebpa for 18h, can be reprogrammed to iPS with extremely high efficiency. To understand the molecular control of this phenomena we performed multiple high throughtput functionnal genomic analysis. Chromatin accessibility by ATACseq in Bcell, Bcell+Cebpa18h, Bcell+Cebpa18h+OKSM1d, Bcell+Cebpa18h+OKSM2d, ES cells
Project description:Heterochromatin is required to restrict aberrant expression of retrotransposons, but it remains poorly defined due to the underlying repeat-rich sequences. We dissected Suv39h-dependent histone H3 lysine 9 trimethylation (H3K9me3) by genome-wide ChIP-sequencing in mouse embryonic stem cells (ESCs). Refined bioinformatic analyses of repeat subfamilies indicated selective accumulation of Suv39h-dependent H3K9me3 at interspersed repetitive elements that cover ~ 5% of the ESC epigenome. The majority of the ~ 8,150 intact long interspersed nuclear elements (LINEs) and endogenous retroviruses (ERVs), but only a minor fraction of the > 1.8 million degenerate and truncated LINEs/ERVs, are enriched for Suv39h-dependent H3K9me3. Transcriptional repression of these intact LINEs and ERVs is differentially regulated by Suv39h and other chromatin modifiers in ESCs but governed by DNA methylation in committed cells. These data provide a novel function for Suv39h-dependent H3K9me3 chromatin to specifically repress intact retrotransposon elements in the ESC epigenome. ChIP-seq and RNA-seq in mouse ES cells, Neural precursors and MEFs wild type and Suv39h double KO. The input for ES cells is accessioned as GSM1251941. A link to this sample can be found below.
Project description:Investigation of gene expression profile changes upon down regulation of p63 in L3.6pl and BxPC-3 cell lines which are representative of the squamous molecular subtype in pancreatic cancer
Project description:During transcription the nascent RNA can invade the DNA template, forming extended RNA-DNA duplexes (R-loops). Here we employ ChIP-seq in strains expressing or lacking RNase H to map targets of RNase H activity throughout budding yeast genome. In wild-type strains, R-loops were readily detected over the 35S rDNA region transcribed by Pol I and over the 5S rDNA transcribed by Pol III. In strains lacking RNase H activity, R-loops were elevated over other Pol III genes notably tRNAs, SCR1 and U6 snRNA, and were also associated with the cDNAs of endogenous TY1 retrotransposons, which showed increased rates of mobility to the 5?-flanking regions of tRNA genes. Unexpectedly, R-loops were also associated with mitochondrial genes in the absence of RNase H1, but not of RNase H2. Finally, R-loops were detected on highly expressed protein-coding genes in the wild-type, notably over the second exon of spliced ribosomal protein genes. ChIP-seq of RNA-DNA hybrids using antibody S9.6
Project description:Since a single miRNA can potentially target hundreds of genes. In parallel, to study the effect of the over-expression of miR-106a-3p on global gene expression patterns, we isolated total RNA from HMEC cells transfected with miR-106a-3p mimic and performed microarray analysis (HG-U133 Plus 2.0).