RpoHI and RpoHII regulons in Rhodobacter sphaeroides 2.4.1 from chromatin immuno-precipitation
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ABSTRACT: In this study, we performed a ChIP-chip experiment to determine the respective regulons of RpoHI and RpoHII in Rhodobacter sphaeroides. We grew R. sphaeroides in aerobic conditions and induced either proteins ectopically and immuno-precipitated the regions of the genomic DNA interacting with the sigma factors. DNA immunoprecipitated with antibodies against RpoHI or RpoHII was labelled with Cy5 and hybridized on two-color tilling arrays (triplicates for each) with genomic DNA as an input control labelled with Cy3.
Project description:We determined the genomic locations of the SigR binding sites by chromatin immuno-precipitation of cross-linked DNA and hybridization on a tilling oligonucleotide array after 20 minutes of diamide treatment on cell cultures. Three independent biological samples were prepared separately from the wild-type cells and pooled before hybridization on a single array. Three more independent biological samples were prepared from sigR deletion mutant cells, pooled, and hybridized on another single array. After normalization, the signal from the mutant cells was subtracted from the signal from the wild-type cells to recover SigR specific signal.
Project description:This SuperSeries is composed of the following subset Series: GSE39711: RpoHI and RpoHII regulons in Rhodobacter sphaeroides 2.4.1 from chromatin immuno-precipitation GSE39712: RpoHI and RpoHII regulons in Rhodobacter sphaeroides 2.4.1 from gene expression profiling Refer to individual Series
Project description:In Rhodobacter sphaeroides a transcriptional response to the reactive oxygen species singlet oxygen is controlled by the group IV sigma factor RpoE and the anti-sigma factor ChrR. In this study, we integrated various large datasets to identify genes within the singlet oxygen stress response that contain RpoE-dependent promoters within R. sphaeroides. Transcript pattern clustering and a RpoE-binding sequence model were used to predict candidate promoters that respond to singlet oxygen stress in R. sphaeroides. These candidate promoters were experimentally validated to nine R. sphaeroides RpoE-dependent promoters that control the transcription of 15 genes activated by singlet oxygen. DNA immunoprecipitated with polyclonal antibodies against RpoE or the Beta' subunit of RNA polymerase was labelled with Cy5 and hybridized on two-color tilling arrays (triplicates for each) with genomic DNA as an input control labelled with Cy3.
Project description:In this study, we performed a ChIP-chip experiment to determine the regulon of FnrL in Rhodobacter sphaeroides. We grew R. sphaeroides under anaerobic photosnthetic conditions, in which FnrL is expected to bind DNA and contol gene expression, and immuno-precipitated FnrL, but also sigma70 and the Beta' subunits of RNA polymerase to determine transcription activity. DNA immunoprecipitated with polyclonal antibodies against FnrL, sigma70, or the Beta' subunit of RNA polymerase was labelled with Cy5 and hybridized on two-color tilling arrays (triplicates for each) with genomic DNA as an input control labelled with Cy3.
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: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: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.
Project description:Epstein-Barr-Virus (EBV) Nuclear Antigens EBNALP and EBNA2 are co-expressed in EBV infected B-lymphocytes and are critical for Lymphoblastoid Cell Line (LCL) growth. EBNALP removes NCOR1 and RBPJ repressive complexes from promoter and enhancer sites and EBNA2 mostly activates transcription from distal enhancers. ChIP-seqs found EBNALP at 19,224 LCL sites, which were 33% promoter associated. EBNALP was associated with 10 transcription factor (TF) clusters that included YY1(63%), SP1(62%), PAX5(59%), BATF(50%), IRF4(49%), RBPJ(43%), ETS1(39%), PU.1(37%), RAD21(33%), NF-kB(31%), TBLR1(26%), ZNF143(24%), CTCF(23%), SMC3(21%), and EBF(17%). EBNALP sites had higher H3K4me3, H3K9ac, H3K27ac, H2Az, and RNA Pol II signals than EBNA2 sites and had similar transcription effects. EBNALP co-localized with 29% of 19,845 EBNA2 sites. EBNALP/EBNA2 sites were similar to EBNALP sites in promoter localization, associated cell TFs, Pol II, H3K4me3, H3K9ac, H3K27ac, and H2Az signals. EBNALP and EBNA2 promoter sites were more transcriptionally active than EBNALP or EBNA2 promoter sites. EBNALP was at the enhancer or promoter of myc and MYC affected genes, including cyclin D2, and bcl2. EBNALP at promoters with DNA looping and transcription factors, is positioned to deplete repressors from enhancers and promoters, enable chromatin remodeling, and transcription activation. Two EBNALP ChIP-seq replicates from IB4 LCL are analyzed in this study.
Project description:The transcription termination factor Rho is a global regulator of RNA polymerase (RNAP). Although individual Rho-dependent terminators have been studied extensively, less is known about the sites of RNAP regulation by Rho on a genome-wide scale. Using chromatin immunoprecipitation and microarrays (ChIP-chip), we examined changes in the distribution of Escherichia coli RNAP in response to the Rho-specific inhibitor bicyclomycin (BCM). We found ~200 Rho-terminated loci that were divided evenly into two classes: intergenic (at the ends of genes) and intragenic (within genes). The intergenic class contained noncoding RNAs such as small RNAs (sRNAs) and transfer RNAs (tRNAs), establishing a previously unappreciated role of Rho in termination of stable RNA synthesis. The intragenic class of terminators included a novel set of short antisense transcripts, as judged by a shift in the distribution of RNAP in BCM-treated cells that was opposite to the direction of the corresponding gene. These Rho-terminated antisense transcripts point to a novel role of noncoding transcription in E. coli gene regulation that may resemble the ubiquitous noncoding transcription recently found to play myriad roles in eukaryotic gene regulation. Chromatin immunoprecipitation (ChIP) experiments were performed using antibodies against RNA polymerase (Beta or Beta' subunit) in cells treated with 20ug/ml bicyclomycin or untreated cells. 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 4 datasets.
Project description:ForJ, ForF and ForZ are cluster situated regulators of the formicamycin biosynthetic gene cluster in Streptomyces forimcae. This ChIP Sequencing experiment was conducted to identify where in the genome these regulators bind in order to identify which transcripts they might regulate.