Chip-chip from Escherichia coli MG1655 K-12, WT and M-bM-^HM-^Ffnr strains
Ontology highlight
ABSTRACT: Mapping the occupancy of FNR, HNS, and IHF throughout the genome of Escherchia coli MG1655 K-12 using an affinity purified antibody under anerobic growth conditions. We also mapped the binding of the M-CM-^_ subunit of RNA Polymerase under both aerobic and anaerobic growth conditions. As a control, we also performed ChIP-chip on FNR in a M-bM-^HM-^Ffnr mutant strain of Escherchia coli MG1655 K-12. We also examined FNR immunoprecipitation at various FNR concentrations using IPTG and Ptac::fnr (PK8263). The M-bM-^HM-^Fhns/M-bM-^HM-^FstpA strains were also used. Descirbed in the manuscript Genome-scale Analysis of E. coli FNR Reveals the Complexity of Bacterial Regulon Structure Mapping of occupancy of FNR, NNS, IHF and M-CM-^_ of RNAP in the genome of Escherchia coli MG1655 K-12 under aerobic or anaerobic growth conditions. Immunoprecipitated DNA compared to INPUT for each sample.
ORGANISM(S): Escherichia coli str. K-12 substr. MG1655
Project description:We found many binding sites for FNR under glucose fermentative anaerobic growth conditions. Also, many binding sites were identified for M-OM-^C70 under both aerobic and anaerobic growthin conditions. Descirbed in the manuscript "Genome-scale Analysis of E. coli FNR Reveals the Complexity of Bacterial Regulon Structure" Examination of occupancy of FNR adn M-OM-^C70 under aerobic and anaerobic growth in conditions.
Project description:Mapping the occupancy of ArcA throughout the genome of Escherchia coli MG1655 K-12 using an affinity purified antibody under anaerobic and aerobic growth conditions. As a control, we also performed ChIP-chip onArcA in a M-bM-^HM-^FarcA mutant strain of Escherchia coli MG1655 K-12. Described in the manuscript The response regulator ArcA uses a diverse binding site architechture to globally regulate carbon oxidation in E. coli Mapping of occupancy of ArcA in the genome of Escherchia coli MG1655 K-12 during anaerobic fermentation and aerobic respiration. Immunoprecipitated DNA compared to INPUT for each sample.
Project description:We found many binding sites for ArcA under glucose fermentative anaerobic growth conditions. Descirbed in the manuscript "The response regulator ArcA uses a diverse binding site architechture to globally regulate carbon oxidation in E. coli" Examination of occupancy of ArcA under anaerobic growth conditions.
Project description:Despite the prevalence of antisense transcripts in bacterial transcriptomes, little is known about how their synthesis is controlled. We report that a major function of the Escherichia coli termination factor Rho and its co-factor NusG is suppression of ubiquitous antisense transcription genome-wide. Rho binds C-rich unstructured nascent RNA (high C/G ratio) prior to its ATP-dependent dissociation of transcription complexes. NusG is required for efficient termination at minority subsets (~20%) of both antisense and sense Rho-dependent terminators with lower C/G ratio sequences. In contrast, a widely studied nusA deletion proposed to compromise Rho-dependent termination had no effect on antisense or sense Rho-dependent terminators in vivo. Global co-localization of the nucleoid-associated protein H-NS with Rho-dependent terminators and genetic interactions between hns and rho suggest that H-NS aids Rho in suppression of antisense transcription. The combined actions of Rho, NusG, and H-NS appear to be analogous to the Sen1-Nrd1-Nab3 and nucleosome systems that suppress antisense transcription in eukaryotes. Chromatin immunoprecipitation (ChIP) experiments were performed using antibodies against RNA polymerase (RNAP; Beta subunit) in wild-type cells or cells deleted for hns, nusG, or a partial deletion of nusA. Differentially labeled ChIP DNA and genomic DNA were competitively hybridized to an E. coli K-12 MG1655 tiling array with overlapping probes at ~12bp spacing across the entire genome. The series contains 12 datasets.
Project description:Chromosomal rearrangements involving ETS factors, ERG and ETV1, occur frequently in prostate cancer. How these factors contribute to tumorigenesis and whether they play similar in vivo roles remain elusive. We show that ERG and ETV1 control a common transcriptional network but in an opposing fashion. In mice with ERG or ETV1 targeted to the endogenous Tmprss2 locus, either factors cooperated with Pten-loss, leading to localized cancer, but only ETV1 supported development of advanced adenocarcinoma, likely through enhancement of androgen receptor signaling and steroid biosynthesis. Indeed, ETV1 expression promotes autonomous testosterone production, which may contribute to tumor progression to castration-resistant prostate cancer. Patient data confirmed association of ETV1 expression with aggressive disease. We conclude that despite many shared targets, ERG and ETV1 contribute differently to prostate tumor biology. Hence, prostate cancers with these fusions should be considered as distinct subtypes for patient stratification and therapy. Genomic targets of ERG and ETV1 transcription factors were identified by antibody-mediated and biotin-mediated ChIP-chip in human VCaP and LNCaP cells, respectively.
Project description:This SuperSeries is composed of the following subset Series: GSE41936: Rho and NusG suppress pervasive antisense transcription in Escherichia coli [ChIP-chip]. GSE41938: Rho and NusG suppress pervasive antisense transcription in Escherichia coli [tiling array]. GSE41939: Rho and NusG suppress pervasive antisense transcription in Escherichia coli [RNA-seq]. Refer to individual Series
Project description:In bacteria, translation-transcription coupling inhibits RNA polymerase (RNAP) stalling. We present evidence suggesting that, upon amino acid starvation, inactive ribosomes promote rather than inhibit RNAP stalling. We developed an algorithm to evaluate genome-wide polymerase progression independently of local noise, and used it to reveal that the transcription factor DksA inhibits promoter-proximal pausing and increases RNAP elongation when uncoupled from translation by depletion of charged tRNAs. DksA has minimal effect on RNAP elongation in vitro and on untranslated RNAs in vivo. In these cases, transcripts can form RNA structures that prevent backtracking. Thus, the effect of DksA on transcript elongation may occur primarily upon ribosome slowing/stalling or at promoter-proximal locations that limit the potential for RNA structure. We propose that inactive ribosomes prevent formation of backtrackblocking mRNA structures and that, in this circumstance, DksA acts as a transcription elongation factor in vivo. Chromatin immunoprecipitation (ChIP) experiments were performed by using antibodies against RNA polymerase b subunit in wild-type and DdksA cells treated with 0.5mg/ml serine hydroxamate (SHX) or untreated. DksA and s70 enrichments were compared to RNAP enrichment by ChIP experiments using antibodies against s70 and DksA in wild-type cells (also in DdksA cells as a negative control for DksA ChIP-chip). Differentially labeled ChIP DNA and genomic DNA were competitively hybridized to an E. coli K-12 MG1655 tiling array with overlapping probes at ~12bp spacing across the entire genome. The series contains 19 datasets.