ChIP-chip of E. coli K-12 MG1655 with antibody against RNA polymerase subunits, RpoB, RpoD, RpoS,RpoH, RpoN, FliA, and FecI
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ABSTRACT:
ORGANISM(S): Escherichia coli str. K-12 substr. MG1655
PROVIDER: GSE46541 | GEO | 2014/02/05
SECONDARY ACCESSION(S): PRJNA202223
REPOSITORIES: GEO
Similar Datasets
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.
2014-02-05 | E-GEOD-46541 | biostudies-arrayexpress
Project description:The RpoN-RpoS alternative sigma factor pathway is essential for key adaptive responses by Borrelia burgdorferi, particularly those involved in the infection of a mammalian host. A putative response regulator, Rrp2, ostensibly is required for activation of the RpoN-dependent transcription of rpoS. However, questions remain regarding the extent to which the three major constituents of this pathway (Rrp2, RpoN, and RpoS) act interdependently. To assess the functional interplay between Rrp2, RpoN, and RpoS, we employed microarray analyses to compare gene expression levels in rrp2, rpoN, or rpoS mutants of parental strain 297. We identified 98 genes that were similarly regulated by Rrp2, RpoN and RpoS, and an additional 47 genes were determined to be likely regulated by this pathway. The substantial overlap between genes regulated by RpoS and RpoN provides compelling evidence that these two alternative sigma factors form a congruous pathway and that RpoN regulates B. burgdorferi gene expression through RpoS. Although several known B. burgdorferi virulence determinants were regulated by the RpoN-RpoS pathway, a defined function has yet to be ascribed to most of the genes substantially regulated by Rrp2, RpoN and RpoS, therefore providing additional avenues for future research into the genetic determinants contributing to virulence expression by B. burgdorferi. Keywords: gene profiling
2008-09-09 | GSE11284 | GEO
Project description:Bacteria generally possess multiple σ factors that, based on structural and functional similarity, divide into two families: σD and σN. Among the seven σ factors in Escherichia coli, six belongs to the σD family. Each σ factor recognizes a group of promoters, providing effective control of differential gene expression. Many studies have shown that σ factors of the σD family compete with each other for function. In contrast, the competition between σN and σD families has yet to be fully explored. Here we report a global antagonistic effect on gene expression between two alternative σ factors, σN (RpoN) and σS (RpoS), a σD family protein. Mutations in rpoS and rpoN inversely affected a number of cellular traits, such as expression of flagellar genes, σN-controlled growth on poor nitrogen sources, and σS-directed expression of acid phosphatase AppA. Transcriptome analysis reveals that 40% of genes in the RpoN regulon were under reciprocal RpoS control. Furthermore, loss of RpoN led to increased levels of RpoS, while RpoN levels were unaffected by rpoS mutations. Expression of the flagellar σF factor (FliA), another σD family protein, was controlled positively by RpoN but negatively by RpoS. These findings unveil a complex regulatory interaction among σN, σS and σF, and underscore the need to employ systems biology approaches to assess the effect of such interaction of σ factors on cellular functions, including motility, nutrient utilization, and stress response.
2010-12-04 | GSE20095 | GEO
Project description:Bacteria generally possess multiple σ factors that, based on structural and functional similarity, divide into two families: σD and σN. Among the seven σ factors in Escherichia coli, six belongs to the σD family. Each σ factor recognizes a group of promoters, providing effective control of differential gene expression. Many studies have shown that σ factors of the σD family compete with each other for function. In contrast, the competition between σN and σD families has yet to be fully explored. Here we report a global antagonistic effect on gene expression between two alternative σ factors, σN (RpoN) and σS (RpoS), a σD family protein. Mutations in rpoS and rpoN inversely affected a number of cellular traits, such as expression of flagellar genes, σN-controlled growth on poor nitrogen sources, and σS-directed expression of acid phosphatase AppA. Transcriptome analysis reveals that 40% of genes in the RpoN regulon were under reciprocal RpoS control. Furthermore, loss of RpoN led to increased levels of RpoS, while RpoN levels were unaffected by rpoS mutations. Expression of the flagellar σF factor (FliA), another σD family protein, was controlled positively by RpoN but negatively by RpoS. These findings unveil a complex regulatory interaction among σN, σS and σF, and underscore the need to employ systems biology approaches to assess the effect of such interaction of σ factors on cellular functions, including motility, nutrient utilization, and stress response. Precise deletion mutants of rpoS or rpoN of MG1655 were constructed and employed in this study. Cultures were inoculated in triplicate in M9 minimal media (0.2% glucose) at a starting OD of 0.0001 and grown aerobically at 37C. Cultures were harvested at OD600 = 0.3 in exponential phase. For RNA extraction, cultures were mixed directly with a boiling lysis buffer containing SDS and EDTA followed by acidic hot phenol to minimize RNA degradation. RNA samples were hybridized to Affymetrix E. coli Genome 2.0 Array according to Affymetrix's standard protocols.
2010-12-04 | E-GEOD-20095 | biostudies-arrayexpress
Project description:The RpoN-RpoS alternative sigma factor pathway is essential for key adaptive responses by Borrelia burgdorferi, particularly those involved in the infection of a mammalian host. A putative response regulator, Rrp2, ostensibly is required for activation of the RpoN-dependent transcription of rpoS. However, questions remain regarding the extent to which the three major constituents of this pathway (Rrp2, RpoN, and RpoS) act interdependently. To assess the functional interplay between Rrp2, RpoN, and RpoS, we employed microarray analyses to compare gene expression levels in rrp2, rpoN, or rpoS mutants of parental strain 297. We identified 98 genes that were similarly regulated by Rrp2, RpoN and RpoS, and an additional 47 genes were determined to be likely regulated by this pathway. The substantial overlap between genes regulated by RpoS and RpoN provides compelling evidence that these two alternative sigma factors form a congruous pathway and that RpoN regulates B. burgdorferi gene expression through RpoS. Although several known B. burgdorferi virulence determinants were regulated by the RpoN-RpoS pathway, a defined function has yet to be ascribed to most of the genes substantially regulated by Rrp2, RpoN and RpoS, therefore providing additional avenues for future research into the genetic determinants contributing to virulence expression by B. burgdorferi. Keywords: gene profiling 297 (wt) vs rpoS mutant: 6 slides, 12 hybridizations (including dyeswaps), three biological replicates 297 (wt) vs rpoN mutant: 5 slides, 10 hybridizations (including dyeswaps), three biological replicates 297 (wt) vs rrp2 mutant: 6 slides, 12 hybridizations (including dyeswaps), three biological replicates 5A18 (wt) vs XY424.3 (rrp2 mutant): 5 slides, 10 hybridizations (including dyeswaps), three biological replicates 297 (wt) vs rpoS mutant: 6 slides, 12 hybridizations (including dyeswaps), three biological replicates 297 (wt) vs rpoN mutant: 5 slides, 10 hybridizations (including dyeswaps), three biological replicates 297 (wt) vs rrp2 mutant: 6 slides, 12 hybridizations (including dyeswaps), three biological replicates 5A18 (wt) vs XY424.3 (rrp2 mutant): 5 slides, 10 hybridizations (including dyeswaps), three biological replicates
2008-09-09 | E-GEOD-11284 | biostudies-arrayexpress
Project description:There is increasing evidence to support a role for sigma factor 54 (RpoN) in the regulation of stress resistance factors and protein secretion systems important to bacterial transmission and pathogenesis. In enterohemorrhagic E. coli O157:H7, acid resistance and type III secretion are essential determinants of gastric passage and colonization. This study thus described the transcriptome of an rpoN null strain of E. coli O157:H7 (EcJR-8) to determine the influence of RpoN on virulence and stress resistance gene regulation, and further explored its contribution to glutamate-dependent acid resistance (GDAR). Inactivation of rpoN resulted in the growth phase-dependent, differential expression of 104 genes. This included type III secretion structural and regulatory genes encoded on the locus of enterocyte effacement (LEE), as well as GDAR genes gadA, gadBC and gadE. Upregulation of gad transcript levels in EcJR-8 during logarithmic growth correlated with increased GDAR and survival in a model stomach. Acid susceptibility was reconstituted in EcJR-8 complemented in trans with wild-type rpoN. Acid resistance in EcJR-8 was dependent on exogenous glutamate, gadE and rpoS, but was independent of hns. Results also suggest that GDAR may be controlled by RpoN at multiple regulatory levels. This study supports the hypothesis that RpoN is an important regulator of virulence and stress resistance factors in E. coli O157:H7, and is the first to examine the mechanism by which it represses GDAR.
2009-08-08 | GSE17467 | GEO
Project description:Alginate overproduction by P. aeruginosa, also known as mucoidy is associated with chronic endobronchial infections in cystic fibrosis (CF). Alginate biosynthesis in this bacterium is initiated by the extracytoplasmic function sigma factor (σ22, AlgU/T). In the wild type (wt) nonmucoid strains, such as PAO1, AlgU is sequestered by the anti-sigma factor MucA that inhibits alginate production. However, the degradation of MucA by activated intramembrane proteases AlgW and/or MucP can lead to the conversion from nonmucoid strains to mucoid. Previously we reported that the absence of the sensor kinase KinB in PAO1 causes the initiation of AlgW-dependent proteolysis of MucA resulting in alginate overproduction. In the kinB mutant this activation requires alternate sigma factor RpoN (σ54). To determine the RpoN-dependent KinB regulon, microarray and proteomic analyses were performed on a mucoid kinB mutant and an isogenic nonmucoid kinB rpoN double mutant. In the kinB mutant, RpoN controlled the expression of approximately 20% of the genome. Besides alginate biosynthesis and regulator genes such as AlgW, KinB, in concert with RpoN, also control a large number of genes including: those involved in carbohydrate metabolism, quorum sensing, iron regulation, rhamnolipid production, and motility. In an acute pneumonia murine infection model, mice exhibited better survival when challenged with the kinB mutant than wt PAO1. Together, these data strongly suggest that KinB controls virulence factors important for acute pneumonia and conversion to mucoidy.
2012-03-01 | GSE35248 | GEO
Project description:The RpoS sigma factor protein of Escherichia coli is the master transcriptional regulator of physiological responses to a variety of stresses. This stress response comes at the expense of scavenging for scarce resources, causing a trade-off between stress tolerance and nutrient acquisition. This trade-off favors non-functional rpoS alleles in nutrient-poor environments. We used experimental evolution to explore how natural selection modifies the regulatory network of strains lacking RpoS when they are evolved in an osmotically stressful environment. We found that strains lacking RpoS adapt less variably, in terms of both fitness increase and changes in patterns of transcription, than strains with functional RpoS. This phenotypic uniformity was caused by the same adaptive mutation in every independent population: the insertion of IS10 into the promoter of otsBA. OtsA and OtsB are required to synthesize the osmoprotectant trehalose, and transcription of otsBA requires RpoS in the wild-type genetic background. The evolved IS10 insertion rewires expression of otsBA from RpoS-dependent to RpoS-independent, allowing for partial restoration of wild-type response to osmotic stress. Our results show that the regulatory networks of bacteria Keywords: evolution; expression
2009-11-10 | GSE13666 | GEO
Project description:In this experiment two strains were compared. The control strain was the wild type strain containing the plasmid, pCD341. pCD341 is an inducible expression vector, a plasmid which can be used to make a bacterium produce a protein of interest. It is called inducible, because the protein of interest will only be produced if an inducer, in this case, IPTG, is present. In the control strain pCD341 is "empty", meaning the gene encoding the protein of interest has not been inserted into the vector, so when you add IPTG nothing will be produced. Because producing plasmid and being exposed to IPTG can stress cells, the wild type strain harboring the "empty" plasmid was used as the control. The experimental strain DL1/pCD341RpoN contained the a "full" vector into which the gene for the sigma factor RpoN was been inserted. Thus when IPTG is added to the growth medium, this strain will overproduce RpoN. RpoN is an alternative sigma factor, a subunit of the RNA polymerase which is required for binding of the polymerase to specific promoters and is therefore required for the transcription of genes with these promoter sequences. Most bacteria have multiple sigma factors, many of which have specialized functions. In many other bacteria, RpoN is required for the expression of genes involved in nitrogen fixation. However, in G.sulfurreducens and myxococcus xanthus, RpoN appears to essential for survival under all conditions tested and its function and promoter specificity are not known. This experiment was performed in order to gain insight into the physiological function of G. sulfurreducens RpoN. Since we could not knock out RpoN, we decided to try overproducing it, hoping that overproducing RpoN would increase expression of genes who's promoters are recognized by RpoN. We took the wild type strain + empty vector and and the wild type strain with the RpoN vector and transferred them both into medium containing IPTG. For this experiment, we used batch cultures, or closed culture containers (no media nutrients or cells flowing in and out). We harvested cells at mid log phase for RNA preparation. There were three biological replicates and two replicate hybridizations were carried out for each. Keywords: cell type comparison
2009-07-13 | GSE8022 | GEO
Project description:RpoS, an alternative sigma factor, is critical for stress response in Escherichia coli.RpoS also acts as a global regulator for stress control of gene expression, and actually dose so in log stage and stationary stage. To further understand the effect of environmental stresses on in ethanologenic strains, DNA microarrys was used to analyze the expression profiles of E. coli and its rpoS mutant strain.
2010-07-20 | GSE17526 | GEO