Coordinate Regulation of Enhancer Transcription at Super-Enhancers
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE60857 | GEO | 2014/12/25
SECONDARY ACCESSION(S): PRJNA259674
REPOSITORIES: GEO
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Project description:Using GRO-Seq, we find extensive regulation of enhancer RNAs (eRNA) within super-enhancers in response to lipopolysaccharide treatment in macrophages. Both activation and repression of gene expression are associated with super-enhancers and eRNA transcription dynamics. Co-treatment of LPS and the anti-inflammatory drug dexamethasone targeted specific super-enhancers by attenuating their eRNA expression, leading to reduced expression of key inflammatory genes. We propose that super-enhancers function as molecular rheostats integrating the binding profiles of key regulators to produce dynamic profiles of gene expression. Nascent transcriptome (GRO-Seq) analysis over a time course (0, 20, 60, 180 min) of Lipopolisaccharide and Dexamethasone signaling in mouse bone marrow-derived macrophages.
2014-12-25 | E-GEOD-60857 | biostudies-arrayexpress
Project description:Rev-Erba and Rev-Erbb are nuclear receptors that regulate the expression of genes involved in the control of circadian rhythm, metabolism, and inflammatory responses. Rev-Erbs function as transcriptional repressors by recruiting NCoR/HDAC3 co-repressor complexes to Rev-Erb response elements in enhancers and promoters of target genes, but the molecular basis for cell-specific programs of repression is not known. Here, we present evidence that in macrophages, Rev-Erbs regulate target gene expression by inhibiting the functions of distal enhancers that are selected by macrophage lineage-determining factors, thereby establishing a macrophage-specific program of repression. Remarkably, the repressive functions of Rev-Erbs are associated with their ability to inhibit the transcription of enhancer-derived RNAs (eRNAs). Furthermore, targeted degradation of eRNAs at two enhancers subject to negative regulation by Rev-Erbs resulted in reduced expression of nearby mRNAs, implying a direct role of these eRNAs in enhancer function. By precisely defining eRNA start sites using a method that quantifies nascent 5' ends (5'-GRO-Seq), we show that transfer of full enhancer activity to a target promoter requires both the sequences mediating transcription factor binding and the specific sequences encoding the eRNA transcript. These studies provide evidence for direct roles of eRNAs in contributing to enhancer functions and suggest that Rev-Erbs act to suppress gene expression at a distance by repressing eRNA transcription. Using ChIPseq, GRO-seq, and 5'GRO-seq to determine mechanism of RevErb in transcriptional regulation in macrophages
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Project description:Enhancers are transcription factor platforms that also bind RNA polymerase II and generate enhancer RNAs (eRNA). Although eRNAs have been suggested as predictors of enhancer activities and possibly key components facilitating transcription, there is little genetic evidence to support this. We address the biology of eRNAs in vivo and investigate eRNA patterns, expression levels and possible functions within a mammary-specific super-enhancer that is composed of three units with distinct transcriptional capacities. We show that eRNA levels do not correspond with the activities of their respective enhancer units. However, changes in eRNA expression upon deletion of individual enhancer units reflect the change in overall super-enhancer activity. These data provide genetic evidence that eRNA levels are not a reliable readout of individual enhancers, but they predict superenhancer activity in the absence of constituent elements.
2018-06-01 | GSE104206 | GEO
Project description:Enhancers play indispensable roles in cell proliferation and survival through spatiotemporally regulating gene transcription. In addition, active enhancers and super-enhancers often produce noncoding enhancer RNAs (eRNAs) that precisely control RNA polymerase II activity. Kaposi’s sarcoma-associated herpesvirus (KSHV) is a human oncogenic gamma-2 herpesvirus that causes Kaposi’s sarcoma and lymphoproliferative diseases of B-cell origin such as primary effusion lymphoma (PEL). It is well characterized that KSHV utilizes host epigenetic and nuclear machineries to control the switch between two life cycles, latency and lytic replication. However, how KSHV impacts the host epigenome at different stages of viral life cycle is not well understood. Using the analysis of global run-on sequencing (GRO-seq) and chromatin-immunoprecipitation sequencing (ChIP-seq), we profiled the dynamics of host transcriptional regulatory elements during latency and lytic replication of KSHV-infected PEL cells. This study showed that a number of critical host genes for KSHV latency, including MYC proto-oncogene, were under the control of super-enhancers and eRNAs that were globally repressed upon viral reactivation. A combination of circular chromosome conformation capture combined with sequencing (4C-seq), GRO-seq and ChIP-seq indicated that the eRNA-expressing super-enhance regions were located at downstream of the MYC gene in KSHV-infected PELs. Treatment of an epigenetic drug to block enhancer function or shRNA-mediated depletion of the eRNA expression significantly reduced MYC mRNA expression in KSHV-infected PELs. Finally, while cellular IRF4 acted upon the eRNAs and super-enhancers for MYC expression during latency, the KSHV viral IRF4 repressed cellular IRF4 expression upon reactivation, decreasing MYC expression and thereby, facilitating lytic replication. Taken together, these data suggest that KSHV acts as an epigenetic driver that modifies host epigenomic status by effectively regulating enhancer function upon reactivation.
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Project description:The functional importance of gene enhancers in regulated gene expression is well established. In addition to widespread transcription of long non-coding RNA (ncRNA) transcripts in mammalian cells, bidirectional ncRNAs referred to as eRNAs are present on enhancers. However, it has remained unclear whether these eRNAs are functional, or merely a reflection of enhancer activation. Here, we report that 17 ?-estradiol (E2)-bound estrogen receptor alpha (ER?) on enhancers causes a global increase in eRNA transcription on enhancers adjacent to E2 upregulated coding genes. These induced eRNAs, as functional transcripts, appear to exert important roles for the observed ligand-dependent induction of target coding genes, causing an increased strength of specific enhancer:promoter looping initiated by ER? binding. Cohesin, present on many ER?-regulated enhancers even prior to ligand treatment, apparently contributes to E2-dependent gene activation by stabilizing E2/ER?/eRNA-induced enhancer:promoter looping. Our data indicate that eRNAs are likely to exert important functions in many regulated programs of gene transcription. The ChIP-seqs in this study measure the binding landscape of master transcription regulator of estrogen signaling - ER?, together with common histone marks including H3K27ac and H3K4me1 in MCF7 cells. These data serve as the basis to understand the enhancer map and subsequent analysis of eRNA expression using GRO-seq. The GRO-seq measures the trancription of nascent RNAs in the genome. From MCF7 cells treated with veichle or estrodial, we could identify estrogen-regulated eRNAs and subsequently could study their functions.
2013-06-04 | E-GEOD-45822 | biostudies-arrayexpress
Project description:Proinflammatory stimuli rapidly and globally remodel chromatin landscape, thereby enabling transcriptional responses. Yet, the mechanisms coupling chromatin regulators to the master regulatory inflammatory transcription factor NF-kB remain poorly understood. We report in human endothelial cells (ECs) that activated NF-kB binds to enhancers, provoking a rapid, global redistribution of BRD4 preferentially at super-enhancers, large enhancer domains highly bound by chromatin regulators. Newly established NF-kB super-enhancers drive nearby canonical inflammatory response genes. In both ECs and macrophages BET bromodomain inhibition prevents super-enhancer formation downstream of NF-kB activation, abrogating proinflammatory transcription. In TNFa-activated endothelium this culminates in functional suppression of leukocyte rolling, adhesion and transmigration. Sustained BET bromodomain inhibitor treatment of LDLr -/- animals suppresses atherogenesis, a disease process rooted in pathological vascular inflammation involving endothelium and macrophages. These data establish BET-bromodomains as key effectors of inflammatory response through their role in the dynamic, global reorganization of super-enhancers during NF-kB activation. Gene expression analysis of human endothelial cells in resting state, treatment with TNFalpha or TNFalpha with the BET bromodomain inhibitor JQ1
2014-09-29 | E-GEOD-53999 | biostudies-arrayexpress
Project description:The discovery that enhancers are regulated transcription units, encoding eRNAs, has raised new questions about the mechanisms of their activation. Here, we report an unexpected molecular mechanism that underlies ligand-dependent enhancer activation, based on DNA nicking to relieve torsional stress from eRNA synthesis. Using dihydrotestosterone (DHT)-induced binding of androgen receptor (AR) to prostate cancer cell enhancers as a model, we show rapid recruitment, within minutes, of DNA topoisomerase I (TOP1) to a large cohort of AR-regulated enhancers. Furthermore, we show that the DNA nicking activity of TOP1 is a prerequisite for robust eRNA synthesis and enhancer activation and is kinetically accompanied by the recruitment of ATR and the MRN complex, followed by additional components of DNA damage repair machinery to the AR-regulated enhancers. Together, our studies reveal a linkage between eRNA synthesis and ligand-dependent TOP1-mediated nicking - a strategy exerting quantitative effects on eRNA expression in regulating AR-bound enhancer-dependent transcriptional programs. Genome-wide binding analysis of AR, TOP1, MRE11 in prostate cancer cell line LNCaP with or without 5alpha-dihydrotestosterone (DHT) treatment. Nascent RNA analysis by global nuclear run-on (GRO-seq) in LNCaP cells transfected with siRNA with or without DHT treatment. Distribution of transcriptionally engaged RNA Pol II in LNCaP cells with or without DHT treatment by precision nuclear run-on and sequencing (PRO-seq).
2015-01-22 | E-GEOD-63202 | biostudies-arrayexpress
Project description:Proinflammatory stimuli rapidly and globally remodel chromatin landscape, thereby enabling transcriptional responses. Yet, the mechanisms coupling chromatin regulators to the master regulatory inflammatory transcription factor NF-kB remain poorly understood. We report in human endothelial cells (ECs) that activated NF-kB binds to enhancers, provoking a rapid, global redistribution of BRD4 preferentially at super-enhancers, large enhancer domains highly bound by chromatin regulators. Newly established NF-kB super-enhancers drive nearby canonical inflammatory response genes. In both ECs and macrophages BET bromodomain inhibition prevents super-enhancer formation downstream of NF-kB activation, abrogating proinflammatory transcription. In TNFa-activated endothelium this culminates in functional suppression of leukocyte rolling, adhesion and transmigration. Sustained BET bromodomain inhibitor treatment of LDLr -/- animals suppresses atherogenesis, a disease process rooted in pathological vascular inflammation involving endothelium and macrophages. These data establish BET-bromodomains as key effectors of inflammatory response through their role in the dynamic, global reorganization of super-enhancers during NF-kB activation. ChIP-Seq for various transcription factors, RNA Polymerase II, and histone modifications in human endothelial cells
2014-09-29 | E-GEOD-53998 | biostudies-arrayexpress
Project description:Proinflammatory stimuli rapidly and globally remodel chromatin landscape, thereby enabling transcriptional responses. Yet, the mechanisms coupling chromatin regulators to the master regulatory inflammatory transcription factor NF-kB remain poorly understood. We report in human endothelial cells (ECs) that activated NF-kB binds to enhancers, provoking a rapid, global redistribution of BRD4 preferentially at super-enhancers, large enhancer domains highly bound by chromatin regulators. Newly established NF-kB super-enhancers drive nearby canonical inflammatory response genes. In both ECs and macrophages BET bromodomain inhibition prevents super-enhancer formation downstream of NF-kB activation, abrogating proinflammatory transcription. In TNFa-activated endothelium this culminates in functional suppression of leukocyte rolling, adhesion and transmigration. Sustained BET bromodomain inhibitor treatment of LDLr -/- animals suppresses atherogenesis, a disease process rooted in pathological vascular inflammation involving endothelium and macrophages. These data establish BET-bromodomains as key effectors of inflammatory response through their role in the dynamic, global reorganization of super-enhancers during NF-kB activation. Chem-Seq for the biotinylated small molecule JQ1 in untreated or TNFalpha treated human endothelial cells
2014-09-29 | E-GEOD-60051 | biostudies-arrayexpress
Project description:Mammalian genomes are populated with thousands of transcriptional enhancers that orchestrate cell type-specific gene expression programs; however, the potential that there are pre-established enhancers in different functional classes that permit alternative signal-dependent transcriptional responses has remained unexplored. Here we present evidence that cell lineage-specific factors, such as FoxA1, can simultaneously facilitate and restrict key regulated transcription factors, exemplified by the androgen receptor (AR), acting at structurally- and functionally-distinct classes of pre-established enhancers, thus licensing specific signal-activated responses while restricting others. Consequently, FoxA1 down-regulation, an unfavorable prognostic sign in advanced prostate tumors, causes a massive switch in AR binding from one functional class of enhancers to another, with a parallel switch in levels of enhancer-templated non-coding RNAs (eRNAs) revealed by the global run-on assay (GRO-seq), which documents the dramatic reprogramming of the hormonal response. The molecular basis for this switch lies in the release of FoxA1-mediated restriction of AR binding to the new enhancer class with no apparent nucleosome remodeling, which is required for stimulating their eRNA transcription and/or enhancing enhancer:promoter looping and gene activation. Together, these findings reveal a large repository of pre-determined enhancers in the human genome that can be dynamically tuned to induce their transcription and activation of alternative gene expression programs, which may underlie many sequential gene expression events in development or during disease progression. ChIP-Seq, Gro-Seq, and gene expression profiling was performed in LNCaP cells with hormone treatment and siRNA against FoxA1 ChIP-Seq and Gro-Seq data presented here. Supplementary file GroSeq.denovo.transcripts.hg18.bed represents analysis using GSM686948-GSM686950.
2011-05-15 | E-GEOD-27823 | biostudies-arrayexpress