ABSTRACT: ChIP-seq was performed using Drosophila Kc167 cells using antibodies against the two isoforms of Fs(1)h, the Brd4 homologue. Differences in binding patterns between the two isoforms are described. We examined the differences in Fs(1)h isoform binding across the genome and describe the short isoform to be correlated with transcription at enhancers and promoters. The long isoform is found predominately at insulator binding sites where multiple insulators are bound.
Project description:ChIP-seq was performed using Drosophila Kc167 cells using antibodies against H3K4me3 to identify active promoters and H3K4me1 to identify active enhancers. H3K27ac ChIPseq was performed to identify active promoters and enhancers. Once enhancers and promoters were identified, JIL-1 and histone phosphorylation, H3K9acS10ph and H3K27acS28ph, ChIP-seq was performed to look at binding trends. JIL-1 and phosphoacetlation is found at low levels at inactive enhancers and shows increase at active enhancers and promoters. Here we examine histone phosphorylation by JIL-1 and acetylation of H3K27ac by CBP at transcriptionally active vs. inactive promoters and enhancers. ChIP-seq is performed in Kc167 Drosophila cells using antibodies against JIL-1, H3K27acS28ph, H3K9acS10ph, H3K4me3, H3K4me1, and H3K27ac.
Project description:H3K27Ac ChIP-seq in wild type and cohesin-deficient thymocytes Rad21 was deleted in CD4+ CD8+ double positive (DP) thymocytes by crossing a Rad21 floxed allele with a Cd4-driven Cre transgene. DP positive thymocytes were FACS-sorted from control and Rad21-/- littermates, which were then used to perform chromatin immunoprecipitation for histone H3 acetylated on lysine 27 (H3K27Ac).
Project description:We mapped the localization of insulator proteins in Drosophila S2 cells in the presence or absence of 12mM of 3AB. We found that inhibition of PARylation affects DNA binding of insulator proteins only at a small subsets of genomic sites. Examination of genomic occupancy for insulator proteins in S2 cells with or without 3AB inhibition.
Project description:Chromosomes of metazoan organisms are partitioned in the interphase nucleus into discrete topologically associating domains (TADs). Borders between TADs are preferentially formed in regions containing high density of active genes and clusters of architectural protein binding sites. Transcription of most genes is turned off during the heat shock response in Drosophila. Here we show that temperature stress induces relocalization of architectural proteins from TAD borders to inside TADs, and this is accompanied by a dramatic rearrangement in the 3D organization of the nucleus. TAD border strength declines, allowing for an increase in long-distance inter-TAD interactions. Similar but quantitatively weaker effects are observed upon inhibition of transcription or depletion of individual architectural proteins. New heat shock-induced inter-TAD interactions result in increased contacts among enhancers and promoters of silenced genes, which recruit Pc and form Pc bodies at the nucleolus. These results suggest that the TAD organization of metazoan genomes is plastic and can be quickly reconfigured to allow new interactions between distant sequences. Analysis of the distribution of architectural proteins, chromatin proteins and histone modifications in Drosophila Kc167 cells. Cells were grown at 25 C (NT) or heat shocked for 20 min at 36.5 C (HS). Both control and reference samples are included. For some of the samples, replicates are also included.
Project description:This SuperSeries is composed of the following subset Series: GSE30686: Gene expression analysis of Kc cells from Drosophila melanogaster during ecdysone treatment and CP190 knockdown GSE30740: Distribution of Drosophila insulator proteins after ecdysone treatment in Kc cells Refer to individual Series
Project description:The ability to measure epigenetic features, such as histone modifications and occupancy by transcription factors and co-activators, on a genome-wide scale is advancing the accuracy of CRM predictions. While integration of signals from multiple features is expected to improve predictions, the contribution of each feature to prediction accuracy is not known. We began with predictions of 4,915 erythroid enhancers based on genomic occupancy by TAL1, a key hematopoietic transcription factor that is strongly associated with gene induction in erythroid cells. Seventy of these DNA segments occupied by TAL1 (TAL1 OSs) were tested by transient transfections of cultured hematopoietic cells, and 56% of these were active as enhancers. Sixty-six TAL1 OSs were evaluated in transgenic mouse embryos, and 65% of these were active enhancers in various tissues. Inclusion of additional epigenetic features improved the prediction accuracy, with combinations of TAL1, GATA1, EP300, H3K4me1, and H3K27ac giving high accuracy of enhancer prediction (70%-75% success depending on method of clustering) while maintaining good sensitivity and specificity. Motifs that distinguish active from inactive TAL1 OSs implicate IRFs, STATs, and FOX protein families as candidate positive co-factors with TAL1, while REST (NRSF) and HOX family proteins are implicated in inactivity. While signals for evolutionary constraint were weak over the entire TAL1-bound DNA segments regardless of activity in either assay, phylogenetic preservation of a TF-binding site motif was associated with enhancer activity. The contribution of 8 epigenetic features including H3K27ac to identification of enhancers in 24h-induced G1E-ER4 cells.
Project description:Here we examine changes in the distribution of Drosophila insulator proteins during the ecdysone response. We performed ChIP-seq analysis in Kc cells at 0, 3, and 48 hours of ecdysone treatment with antibodies against CP190, Su(Hw), dCTCF, and BEAF-32B. Examination of 4 different insulator proteins at 3 time points of ecdysone treatment.
Project description:Polycomb group (PcG) proteins play important roles in repressing lineage-specific genes and maintaining the undifferentiated state of mouse embryonic stem cells (mESCs). However, the mechanisms by which PcG proteins are recruited to their targets are largely unknown. Here, we show that the histone demethylase Kdm2b is highly expressed in mESCs and regulated by the pluripotent factors Oct4/Sox2 directly. Depletion of Kdm2b in mESCs causes de-repression of lineage-specific genes and induces early differentiation. The function of Kdm2b depends on its CXXC-ZF domain, which mediates Kdm2b’s genome-wide binding to CpG islands (CGIs). Kdm2b interacts with the core components of the Polycomb repressive complex 1 (PRC1) and recruits the complex to the CGIs of early lineage-specific genes. Thus, our study not only reveals a novel Oct4/Sox2-Kdm2b-PRC1-CGI regulatory axis and its function in maintaining undifferentiated state of mESCs, but also demonstrates a critical function of Kdm2b in recruiting PRC1 to the CGIs of lineage-specific genes to repress their expression. In this dataset, we include the ChIP-seq data of Kdm2b, Ezh2 and Ring1b in both control and Kdm2b knock down mouse embryonbic stem cells.
Project description:Ten-eleven translocation (Tet) family of DNA dioxygenases converts 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5- carboxylcytosine (5caC) through iterative oxidation reactions. While 5mC and 5hmC are relatively abundant, 5fC and 5caC are at very low levels in the mammalian genome. Thymine DNA glycosylase (TDG) and base excision repair (BER) pathways can actively remove 5fC/5caC to regenerate unmethylated cytosine, but it is unclear to what extent and at which part of the genome such active demethylation processes take place. Here, we have performed high-throughput sequencing analysis of 5mC/5hmC/5fC/5caC- enriched DNA using modification-specific antibodies and generated genome-wide distribution maps of these cytosine modifications in wild-type and Tdg-deficient mouse embryonic stem cells (ESCs). We observe that the steady state 5fC and 5caC are preferentially detected at repetitive sequences in wild-type mouse ESCs. Depletion of TDG causes marked accumulation of 5fC and 5caC at a large number of distal gene regulatory elements and transcriptionally repressed/poised gene promoters, suggesting that Tet/TDG-dependent dynamic cycling of 5mC oxidation states may be involved in regulating the function of these regions. Thus, comprehensive mapping of 5mC oxidation and BER pathway activity in the mammalian genome provides a promising approach for better understanding of biological roles of DNA methylation and demethylation dynamics in development and diseases. In this dataset, we include the DIP-seq data of 5mC, 5hmC, 5fC and 5caC in both control and Tdg knockdown mouse embryonic stem cells.