Project description:We report changes in GR and Pol II binding profiles genome-wide upon treatment with corticosterone (Cort) for 20 minutes, treatment with Cort for 20 minutes followed by hormone withdrawal for 40 minutes, 60 minutes continuous stimulation with Cort, and 60 minutes continuous stimulation with Dexamethasone (Dex). We examine GR binding upon following treatments: 0' Cort, 20' Cort, 60' Cort Pulsed, 60' Cort Constant; Pol II binding upon following treatments: 0' Cort, 20' Cort, 60' Cort Pulsed, 60' Cort Constant, 60' Dex Constant; Pol II binding upon Mock treatments simulating 0' Cort, 20' Cort, 60' Cort Pulsed, 60' Cort Constant; CTCF binding profile of untreated cells.
Project description:We report changes in ER and GR binding profiles genome-wide upon co-treatment with Dex and E2 when compared to Dex or E2 treatments alone. We examine ER and GR binding under four different treatments (unt, Dex, E2, and Dex + E2).
Project description:Hox genes are essential regulators of embryonic development. They are activated in a temporal sequence following their topological order within their genomic clusters. Subsequently, states of activity are fine-tuned and maintained to translate into domains of progressively overlapping gene products. While the mechanisms underlying such temporal and spatial progressions begin to be understood, many of their aspects remain unclear. We have systematically analyzed the 3D chromatin organization of Hox clusters in vivo, during their activation using high-resolution circular chromosome conformation capture (4C-seq). Initially, Hox clusters are organized as single 3D chromatin compartments decorated with bivalent chromatin marks. Their progressive transcriptional activation is associated with a dynamic bi-modal 3D organization, whereby the genes switch one after the other, from an inactive to an active 3D compartment. These local 3D dynamics occur within a larger constitutive framework of interactions within the surrounding Topological Associated Domains, which confirms previous results that regulation of this process in primarily cluster intrinsic. The local step-wise progression in time can be stopped and memorized at various body levels and hence it may accounts for the various chromatin architectures previously described at different anterior to posterior body levels for the same embryo at a later stage. ChIP-seq samples (H3K4me3 and H3K27me3) from mouse ES cells and mouse embryonic stage E8.5 pre-somitic mesoderm. Data based on 4 biological samples.
Project description:Chromatin-organizing factors, like CTCF and cohesins, have been implicated in the control of complex viral regulatory programs. We investigated the role of CTCF and cohesin in the control of the latent to lytic switch for Kaposi's Sarcoma-Associated Herpesvirus (KSHV). We found that cohesin subunits, but not CTCF, were required for the repression of KSHV immediate early gene transcription. Depletion of cohesin subunits Rad21, SMC1, or SMC3 resulted in lytic cycle gene transcription and viral DNA replication. In contrast, depletion of CTCF failed to induce lytic transcription or DNA replication. ChiP-Seq analysis revealed that cohesins and CTCF bound to several sites within the immediate early control regions for ORF50 and more distal 5' sites that also regulate the divergently transcribed ORF45-46-47 gene cluster. Rad21 depletion led to a robust increase in ORF45 and ORF47 transcripts, with similar kinetics to that observed with chemical induction by sodium butyrate. During latency, the chromatin between the ORF45 and ORF50 transcription start sites was enriched in histone H3K4me3 with elevated H3K9ac at the ORF45 promoter and elevated H3K27me3 at the ORF50 promoter. A paused form of RNA pol II was loosely associated with the ORF45 promoter region during latency, but was converted to an active elongating form upon reactivation induced by Rad21 depletion. Butyrate-induced transcription of ORF45 and ORF47 was resistant to cyclohexamide, suggesting that these genes have immediate early features similar to ORF50. Butyrate-treatment caused the rapid dissociation of cohesins and loss of CTCF binding at the immediate early gene locus, suggesting that cohesins may be a direct target of butyrate-mediated lytic induction. Our findings implicate cohesins as a major repressor of KSHV lytic gene activation, and function coordinately with CTCF to regulate the switch between latent and lytic gene activity. Study of chromatin-organizing factors, like CTCF and cohesins.
Project description:We have performed ChIP seq analysis to obtain the positions of KAP1 and ZFP57 binding sites in mouse ES cells. By comparing the two lists, we were able to find bona fide sites. ChIP-Seq of HA tagged ZFP57 and KAP1 in mouse ES cells
Project description:SOX9 is a transcriptional activator required for chondrogenesis, and SOX5 and SOX6 are closely related DNA-binding proteins that critically enhance its function. We used RNA-seq to charatierize a rat chondrosarcoma (RCS) cells as a faithful model for proliferating/early prehypertrophic growth plate chondrocytes and ChIP-seq to gain novel insights into the full spectrum of the target genes and modes of action of this chondrogenic trio. ChIP-seq for SOX9, SOX6 and histone modifications were carried out using RCS cells
Project description:DEAD-box RNA helicases are vital for the regulation of various aspects of the RNA life cycle, but the molecular underpinnings of their involvement, particularly in mammalian cells, remain poorly understood. Here we show that the DEAD-box RNA helicase DDX21 can sense transcriptional status of both RNA Pol I and Pol II to control transcriptional and post-transcriptional steps of ribosome biogenesis in human cells. We demonstrate that DDX21 widely associates with Pol I- and Pol II-transcribed genes and with diverse species of protein-coding and noncoding RNAs. Although broad, these molecular interactions, both at the chromatin and at the RNA level, exhibit a remarkable specificity for the ribosomal pathway. In the nucleolus, DDX21 occupies the transcribed rDNA locus, directly contacts both rRNA and snoRNAs and, as a functional component of the snoRNA ribonucleoprotein (snoRNP) complex, promotes modification of rRNA. In the nucleoplasm, DDX21 is incorporated into the 7SK snRNP complex, which facilitates DDX21 association with promoters of Pol II-transcribed genes encoding ribosomal proteins and snoRNAs. Promoter-bound DDX21 facilitates the release of P-TEFb from the 7SK snRNP, enhancing productive Pol II elongation. Altogether, we present a unifying mechanism for the coordinated regulation of ribosomal genes across nuclear compartments, and provide first evidence implicating a mammalian RNA helicase in RNA modification and Pol II elongation control. Examination of DDX21 chromatin association and DDX21 RNA interacting partners in HEK293 cells