Project description:Determining how facultative anaerobic organisms sense and direct cellular responses to electron acceptor availability has been a subject of intense study. However, even in the model organism Escherichia coli, established mechanisms only explain a small fraction of the hundreds of genes that are regulated during shifts in electron acceptor availability. Here we propose a qualitative model that accounts for the full breadth of regulated genes by detailing how two global transcription factors (TFs), ArcA and Fnr of E. coli, sense key metabolic redox ratios and act on a genome-wide basis to regulate anabolic, catabolic, and energy generation pathways. We first fill gaps in our knowledge of this transcriptional regulatory network by carrying out ChIP-chip and gene expression experiments to identify 463 regulatory events. We then interfaced this reconstructed regulatory network with a highly curated genome-scale metabolic model to show that ArcA and Fnr regulate > 80% of total metabolic flux and 96% of differential gene expression across fermentative and nitrate respiratory conditions. Finally, based on the data we propose a feedforward with feedback trim regulatory scheme by showing extensive repression of catabolic genes by ArcA and extensive activation of chemiosmotic genes by Fnr. We further corroborated this regulatory scheme by showing a 0.71 r2 (p < 1e-6) correlation between changes in metabolic flux and changes in regulatory activity across fermentative and nitrate respiratory conditions. We also are able to relate the proposed model to a wealth of previously generated data by contextualizing the existing transcriptional regulatory network. We integrated transcription factor binding regions and mRNA transcript abundance to elucidate the ArcA and Fnr regulons experimentally. To measure transcription factor binding at a genome scale, we employed a ChIP-chip method to derivative strains of E. coli K-12 MG1655 harboring ArcA-8myc or Fnr-8myc under various conditions. The E. coli strains harboring Fnr-8myc and ArcA-8myc were generated as described previously [PMID 16454042]. A 12 chip study with two different strains under two different culture conditions.
Project description:We integrated transcription factor binding regions and mRNA transcript abundance to elucidate the ArgR, Lrp, and TrpR regulon experimentally. To measure transcription factor binding at a genome scale, we employed a ChIP-chip method to derivative strains of E. coli K-12 MG1655 harboring ArgR-8myc, Lrp-8myc, or TrpR-8myc under various conditions. A twelve ChIP-chip study under six separate culture conditions. The high-density oligonucleotide tiling arrays used were consisted of 371,034 oligonucleotide probes spaced 25 bp apart (25-bp overlap between two probes) across the E. coli genome.
Project description:We integrated transcription factor binding regions and mRNA transcript abundance to elucidate the PurR regulon experimentally. To measure transcription factor binding at a genome scale, we employed a ChIP-chip method to derivative strains of E. coli K-12 MG1655 harboring PurR-8myc under various conditions. A four ChIP-chip study under two separate culture conditions. The high-density oligonucleotide tiling arrays used were consisted of 371,034 oligonucleotide probes spaced 25 bp apart (25-bp overlap between two probes) across the E. coli genome.
Project description:This SuperSeries is composed of the following subset Series: GSE26588: Transcriptome analysis of E. coli MG1655 GSE26589: ChIP-chip of E. coli K-12 MG1655 with antibody against PurR-8myc under various conditions. Refer to individual Series
Project description:We applied a ChIP-chip approach to elucidate the binding profiles of sigma factors (RpH, RpoN and RpoS) experimentally under different growth conditions. This technique localizes DNA fragments within DNA-protein complexes enriched by chromatin immunoprecipitation using high-density oligonucleotide tilling arrays. A 10 ChIP-chip study using immunoprecipitated DNA (IP-DNA) from three culture condtions against three alternative sigma factors . The high-density oligonucleotide tiling arrays used were consisted of 381,174 oligonucleotide probes spaced 20 bp apart (30-bp overlap between two probes) across the G.sulfurreducens genome (NimbleGen). Experiments were conducted as three bioliogical replicates (different cultures).
Project description:We applied a ChIP-chip approach to elucidate the σN regulon experimentally under different growth conditions. This technique localizes DNA fragments within σN complexes enriched by chromatin immunoprecipitation using high-density oligonucleotide tilling arrays. A nine ChIP-chip study using immunoprecipitated DNA (IP-DNA) from three separate culture conditions. The high-density oligonucleotide tiling arrays used were consisted of 381,174 oligonucleotide probes spaced 20 bp apart (30-bp overlap between two probes) across the G.sulfurreducens genome (NimbleGen). Experiments were conducted as three bioliogical replicates (different cultures)
Project description:This SuperSeries is composed of the following subset Series: GSE17834: Transcriptome analysis of Geobacter sulfurreducens grown with different nitrogen sources GSE17837: ChIP-chip of Geobacter sulfurreducens PCA with antibody against RpoN under various conditions. Refer to individual Series
Project description:We applied a ChIP-chip approach to elucidate the binding profiles of RNAP and RpoD experimentally under different growth conditions. This technique localizes DNA fragments within DNA-protein complexes enriched by chromatin immunoprecipitation using high-density oligonucleotide tilling arrays. A 21 ChIP-chip study using immunoprecipitated DNA (IP-DNA) from three culture conditions for RNAP and four culture conditions for RpoD. The high-density oligonucleotide tiling arrays used consisted of 381,174 oligonucleotide probes spaced 20 bp apart (30-bp overlap between two probes) across the G. sulfurreducens genome (NimbleGen). Experiments were conducted as three bioliogical replicates (different cultures).
Project description:We investigate sigma factor binding regions for each sigma factor under various enviromental and/or genetic conditions. To measure sigma factor binding at a genome scale, we employed a ChIP-chip method to derivative strains of E. coli K-12 MG1655 wild type and its isogenic rpoS and rpoN knock-out strains under various conditions. A 45 ChIP-chip study under 4 separate culture conditions. The high-density oligonucleotide tiling arrays used were consisted of 371,034 oligonucleotide probes spaced 25 bp apart (25-bp overlap between two probes) across the E. coli genome.
Project description:We integrated RNAP binding regions (RBRs) and mRNA transcript abundance to determine segments of contiguous transcription originating from promoter regions. To measure RBRs at a genome scale, we employed a ChIP-chip method to E. coli K-12 MG1655 grown in the presence or absence of rifampicin under multiple growth conditions using antibody against E. coli RNAP beta subunit. A twelve ChIP-chip study using immunoprecipitated DNA (IP-DNA) from four separate culture conditions with and/or without rifampicin treatment. The high-density oligonucleotide tiling arrays used were consisted of 371,034 oligonucleotide probes spaced 25 bp apart (25-bp overlap between two probes) across the E. coli genome (NimbleGen). Experiments were conducted as biological duplicates or triplicates (different cultures).