ChIP-seq of GFP-tagged dCoREST, dLSD1, dL(3)mbt and dG9a in D. melanogaster S2 cell lines
Ontology highlight
ABSTRACT: We employed CRISPR/Cas-mediated genome editing to generate S2 cell lines expressing GFP-tagged dCoREST, dL(3)mbt, dLSD1 and dG9a, respectively. This allowed us to determine the genome-wide binding profiles for these proteins by ChIP-seq using the same antibody (anti-GFP) in each case.
Project description:Mutations in the l(3)mbt tumour suppressor result in overproliferation of Drosophila larval brains. Recently, the derepression of different gene classes in l(3)mbt mutants was shown to be causal for transformation. However, the molecular mechanisms of dL(3)mbt-mediated gene repression are not understood. Here, we identify LINT, the major dL(3)mbt complex of Drosophila. LINT has three core subunits-dL(3)mbt, dCoREST, and dLint-1-and is expressed in cell lines, embryos, and larval brain. Using genome-wide ChIP-Seq analysis, we show that dLint-1 binds close to the TSS of tumour-relevant target genes. Depletion of the LINT core subunits results in derepression of these genes. By contrast, histone deacetylase, histone methylase, and histone demethylase activities are not required to maintain repression. Our results support a direct role of LINT in the repression of brain tumour-relevant target genes by restricting promoter access.
Project description:Metazoan transcription is controlled through either coordinated recruitment of transcription machinery to the gene promoter, or subsequently, through regulated pausing of RNA polymerase II (Pol II) in early elongation. We report that a key difference between genes that use these distinct regulatory strategies lies in the chromatin architecture specified by their DNA sequences. Pol II pausing is prominent at highly-regulated genes whose sequences inherently disfavor nucleosome formation within the gene, but favor nucleosomal occlusion of the promoter. Pausing of polymerase maintains these genes in an active state by inhibiting the formation of repressive promoter chromatin. In contrast, promoters of housekeeping genes that lack paused Pol II are deprived of nucleosomes regardless of polymerase binding, but show higher nucleosome occupancy downstream. Our results suggest that the âdefaultâ chromatin state of a gene instructs its regulation, and that highly-regulated promoters have evolved to encourage competition between nucleosomes and paused Pol II for promoter occupancy. All experiments were done using two channels per chip, comparing DNA immunoprecipitated by the indicated antibody to matching input chromatin used for affinity purification. Where appropriate, replicate data sets were averaged.
Project description:The proper balance of excitatory and inhibitory neurons is crucial to normal processing of somatosensory information in the dorsal spinal cord. Two neural basic helix-loop-helix transcription factors, Ascl1 and Ptf1a, are essential for generating the correct number and sub-type of neurons in multiple regions of the nervous system. M-BM- In the dorsal spinal cord, Ascl1 and Ptf1a have contrasting functions in specifying inhibitory versus excitatory neurons. To understand how Ascl1 and Ptf1a function in these processes, we identified their direct transcriptional targets genome-wide in the embryonic mouse neural tube using ChIP-Seq and RNA-Seq. We show that Ascl1 and Ptf1a regulate the specification of excitatory and inhibitory neurons in the dorsal spinal cord through direct regulation of distinct homeodomain transcription factors known for their function in neuronal sub-type specification. Besides their roles in regulating these homeodomain factors, Ascl1 and Ptf1a each function differently during neuronal development with Ascl1 directly regulating genes with roles in several steps of the neurogenic program including, Notch signaling, neuronal differentiation, axon guidance, and synapse formation. In contrast, Ptf1a directly regulates genes encoding components of the neurotransmitter machinery in inhibitory neurons, and other later aspects of neural development distinct from those regulated by Ascl1. Moreover, Ptf1a represses the excitatory neuronal fate by directly repressing several targets of Ascl1. Examination of the Ascl1 and Ptf1a bound sequences shows they are enriched for a common E-Box with a GC core and with additional motifs used by Sox, Rfx, Pou, and Homeodomain factors. Ptf1a bound sequences are uniquely enriched in an E-Box with a GA/TC core and in the binding motif for its co-factor Rbpj, providing two keys to specificity of Ptf1a binding. The direct transcriptional targets identified for Ascl1 and Ptf1a provide a molecular understanding for how they function in neuronal development, particularly as key regulators of homeodomain transcription factors required for neuronal sub-type specification. Examination of Ascl1 and Ptf1a genome-wide binding in developing neural tube.
Project description:Drosophila melanogaster KC cells were treated with RNAi against dL(3)mbt, dLint1 or EGFP (control) and the resulting changes in gene expression were measured.
Project description:The mouse S180A (SA) mutation of the Trp53 is a p53 phosphorylation-deficient mutant protein with native conformation. Here we want to assess the impact of DNA binding site phosphorylation of the p53 target gene spectrum and transcriptional activity under untreated conditions and following p53 stabilization with the Mdm2 inhibitor nutlin-3a.
Project description:We have used a genome-wide ChIP-sequencing approach to define and investigate the dynamics of the cis-regulatory landscape in three developmental stages of the murine hematopoietic system. To this end, we have compared the profiles of H3K4me3, H3K4me1, H3K27ac, H3K27me3 and H3K9me2 in HSCs, committed pro-B and splenic mature B cells. We find the enhancer repertoire to be dynamically reshaped during hematopoiesis progression, surprisingly only a small fraction of primed enhancers in HSCs or committed progenitors become activated in subsequent stages. In turn, the majority of active enhancers in terminally differentiated cells are not primed in earlier stages. We also found that The heterochromatin mark H3K9me2 covers large domains that remain largerly invariant across the three stages and are depleted in both active chromatin marks and the Polycomb related mark H3K27me3. Investigating enhancer dynamics in 3 different stages of B cell development
Project description:ChIP-chip experiment for nuclear pore proteins Nup153 and Mtor in Drosophila S2 and Kc cells. This experiment is related to E-MEXP-2523.
Project description:The mouse R178E (EE) mutation of the Trp53 is a p53 mutant protein with native conformation that lacks the ability to form tetramers and thus constitutes a mutant form of p53 that lacks DNA binding cooperativity. Here we want to assess DNA binding ability of the EE mutant in MEFs under untreated conditions and following p53 stabilization with the Mdm2 inhibitor nutlin-3a and compare it to p53 KO and WT mice.
Project description:Regulation of gene expression by chromatin modification through methylation of histone lysine residues is a dynamic, reversible process that when deregulated is associated with cancer development. In multiple myeloma, combined inhibition of the histone demethylases JARID1B, UTX and JmjD3 by the small molecule GSK-J4 prevents cellular glutamine utilization leading to amino acids deprivation, activates the integrated stress response via GCN2-dependent ATF4 activation, and induces apoptosis. This response is associated with a profound upregulation of metallothionein genes. Combined with clinical data demonstrating that overexpression of JARID1B is associated with shorter survival in multiple myeloma patients, this study highlights histone demethylases as epigenetic drug targets and places this demethylase inhibitor chemotype as having unique potential relative to established anti-myeloma treatment options. In total there are 7 different samples analyzed and one input control. Treatments are carried out with the demethylase inhibitor (or DMSO as negative control) at 6h and 48h, or with LNA targeting demethylases (or scrambled LNA) at 7 days. A negative control at 0h is included.