Identification of StpA-binding sites on the Salmonella genome
Ontology highlight
ABSTRACT:
ORGANISM(S): Salmonella enterica subsp. enterica serovar Typhimurium Salmonella enterica subsp. enterica serovar Typhimurium str. SL1344
PROVIDER: GSE18450 | GEO | 2009/10/28
SECONDARY ACCESSION(S): PRJNA123325
REPOSITORIES: GEO
Similar Datasets
Project description:We used ChIP-chip analysis to identify where the nucleoid associated protein StpA binds on the Salmonella Typhimurium genome. We identified 285 chromosomal regions bound by StpA, ranging in size from 400 to 3500 base pairs and containing 572 genes. Comparison of the ChIP data revealed that StpA displayed an identical binding profile to H-NS; all genomic regions associated with StpA were also bound by H-NS. Of the 88 StpA-dependent genes that are de-repressed in the absence of StpA, only 25 were bound by StpA, suggesting that StpA generally regulates gene expression indirectly. To identify the direct StpA targets, we co-immunoprecipitated DNA from a strain expressing a 3xFLAG-tagged StpA-protein using an anti-3xFLAG antibody. As a negative control, we used the same antibody (anti-3xFLAG) to co-immunoprecipitate DNA from an isogenic strain expressing the non-tagged StpA-protein. Three independent biological replicates were generated. For comparative purposes we also performed the co-immunoprecipitation on wild type Salmonella using a monoclonal anti-H-NS antibody. In that case, the negative control was obtained by performing the co-immunoprecipitation protocol on wild type Salmonella without adding antibody.
2009-10-28 | E-GEOD-18450 | biostudies-arrayexpress
Project description:StpA is a paralogue of the nucleoid associated protein H-NS that is conserved in a range of enteric bacteria and had no known function in Salmonella enterica serovar Typhimurium. Here, we show that 5% of the Salmonella genome is regulated by StpA, which contrasts with the situation in Escherichia coli where deletion of stpA only had minor effects on gene expression. The StpA-dependent genes of S. Typhimurium are a specific subset of the H-NS regulon that are predominantly under the positive control of sigma38 (RpoS), CRP-cAMP and PhoP. The regulatory role of StpA varied at different growth phases; StpA only controlled sigma38 levels at mid-exponential phase when it prevented inappropriate activation of sigma38 during rapid bacterial growth. In contrast, StpA only activated the CRP-cAMP regulon during late exponential phase.
2009-10-28 | GSE18428 | GEO
Project description:StpA is a paralogue of the nucleoid associated protein H-NS that is conserved in a range of enteric bacteria and had no known function in Salmonella enterica serovar Typhimurium. Here, we show that 5% of the Salmonella genome is regulated by StpA, which contrasts with the situation in Escherichia coli where deletion of stpA only had minor effects on gene expression. The StpA-dependent genes of S. Typhimurium are a specific subset of the H-NS regulon that are predominantly under the positive control of sigma38 (RpoS), CRP-cAMP and PhoP. The regulatory role of StpA varied at different growth phases; StpA only controlled sigma38 levels at mid-exponential phase when it prevented inappropriate activation of sigma38 during rapid bacterial growth. In contrast, StpA only activated the CRP-cAMP regulon during late exponential phase.
2009-10-28 | GSE18424 | GEO
Project description:Expression of virulence genes in pathogenic E. coli is controlled in part by the transcription silencer H-NS and its paralogs (e.g., StpA), which sequester DNA in multi-kb nucleoprotein filaments to inhibit transcription initiation, elongation, or both. Some activators counter-silence initiation by displacing H-NS from promoters. How H-NS inhibition of elongation is overcome is not understood. In uropathogenic E. coli (UPEC), elongation regulator RfaH aids expression of some H-NS-silenced pathogenicity operons (e.g., hlyCABD encoding hemolysin). RfaH associates with elongation complexes (ECs) via direct contacts to a transiently exposed, nontemplate DNA-strand sequence called ops (operon polarity suppressor). RfaH–ops interactions establish long-lived RfaH–EC contacts that allow RfaH to recruit ribosomes to the nascent mRNA and to suppress transcriptional pausing and termination. Using ChIP-seq, we mapped the genome-scale distributions of RfaH, H-NS, StpA, RNA polymerase (RNAP), and σ70 in the UPEC strain CFT073. We identify 8 RfaH-activated operons, all of which were bound by H-NS and StpA. Four are new additions to the RfaH regulon. Deletion of RfaH caused premature termination whereas deletion of H-NS and StpA allowed elongation without RfaH. Thus, RfaH is an elongation counter-silencer of H-NS. Consistent with elongation counter-silencing, deletion of StpA alone decreased the effect of RfaH. StpA increases DNA bridging, which inhibits transcript elongation via topological constraints on RNAP. Residual RfaH effect when both H-NS and StpA were deleted was attributable to targeting of RfaH-regulated operons by a minor H-NS paralog, Hfp. These operons have evolved higher levels of H-NS–binding features, explaining minor-paralog targeting.
2022-10-06 | GSE212064 | GEO
Project description:StpA is a paralogue of the nucleoid associated protein H-NS that is conserved in a range of enteric bacteria and had no known function in Salmonella enterica serovar Typhimurium. Here, we show that 5% of the Salmonella genome is regulated by StpA, which contrasts with the situation in Escherichia coli where deletion of stpA only had minor effects on gene expression. The StpA-dependent genes of S. Typhimurium are a specific subset of the H-NS regulon that are predominantly under the positive control of sigma38 (RpoS), CRP-cAMP and PhoP. The regulatory role of StpA varied at different growth phases; StpA only controlled sigma38 levels at mid-exponential phase when it prevented inappropriate activation of sigma38 during rapid bacterial growth. In contrast, StpA only activated the CRP-cAMP regulon during late exponential phase. To test the hypothesis that stpA prevents Sigma38-dependent transcription during mid-exponential growth in S. Typhimurium, we analysed the effect of the stpA deletion on transcription in the presence and absence of rpoS. Three biological replicates were performed for each strain. For this study, we used Salmonella genomic DNA as the comparator which also acted as the control for spot quality.
2010-06-20 | E-GEOD-18428 | biostudies-arrayexpress
Project description:StpA is a paralogue of the nucleoid associated protein H-NS that is conserved in a range of enteric bacteria and had no known function in Salmonella enterica serovar Typhimurium. Here, we show that 5% of the Salmonella genome is regulated by StpA, which contrasts with the situation in Escherichia coli where deletion of stpA only had minor effects on gene expression. The StpA-dependent genes of S. Typhimurium are a specific subset of the H-NS regulon that are predominantly under the positive control of sigma38 (RpoS), CRP-cAMP and PhoP. The regulatory role of StpA varied at different growth phases; StpA only controlled sigma38 levels at mid-exponential phase when it prevented inappropriate activation of sigma38 during rapid bacterial growth. In contrast, StpA only activated the CRP-cAMP regulon during late exponential phase. The effect of stpA deletion on S. Typhimurium gene expression during growth in LB was analysed at 4 different time points (early-log, mid-log, late-log, and stationary phase) where the gene expression profile of the stpA-deletion strain was compared to that of the parental strain. Between two and three biological replicates were performed for each strain and time point. For this study, we used Salmonella genomic DNA as the comparator which also acted as the control for spot quality.
2009-10-27 | E-GEOD-18424 | biostudies-arrayexpress
Project description:StpA and H-NS distribution in Escherichia coli
2009-03-13 | E-MEXP-1880 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the following subset Series: GSE18424: The effect of stpA deletion on S. Typhimurium gene expression during growth in rich medium GSE18428: StpA prevents RpoS-dependent transcription during mid-exponential growth in S. Typhimurium GSE18450: Identification of StpA-binding sites on the Salmonella genome Refer to individual Series
2010-06-21 | E-GEOD-18452 | biostudies-arrayexpress
Project description:The global regulator, H-NS, controls genes related to stress response, biofilm formation, and virulence expression by recognizing the curved DNA and silences gene transcription acquired from lateral gene transfer. Here, we rewired H-NS to control biofilm formation using protein engineering. One H-NS variant, H-NS K57N was obtained to reduce biofilm formation 10-fold compared to H-NS wild-type. Whole-transcriptome analysis (BW25113 hha hns / pCA24N-hns K57N vs. BW25113 hha hns / pCA24N-hns) revealed that H-NS K57N represses biofilm formation through the interactinon with other nucleoid proteins, Cnu and StpA. Remarkably, H-NS K57N enhanced the excision of defective prophage Rac while H-NS wild-type represses it, and H-NS controlled only Rac excision among E. coli prophages. These results imply that the repression of Rac excision is one of the silencing manner for foreign genes by H-NS. Also, the prophage excision not only led to the change of biofilm formation but also resulted in cell lysis through the expression of toxin protein HokD with reduced viability, which are important for cell physiology in response to the change of environmental conditions. Hence, H-NS regulatory system may be evolved easily with specialized functions in terms of biofilm formation, prophage control, and cell lysis.
2010-02-22 | GSE17853 | GEO
Project description:Among the most important regulators of gene expression in bacteria are 'nucleoid-associated proteins'. These proteins alter the topology of the bound DNA by bending, wrapping or bridging it, thus having multiple effects, including transcriptional regulation, on the bacterial cell. Among the best-studied nucleoid proteins are H-NS and Fis, which bind to specific sequences on the DNA. H-NS is a global repressor of gene expression. Fis alters the global conformation of the DNA by introducing branched structures in it; but its effect on gene expression on a genomic scale remains largely unclear.<br><br>Several bacterial transcriptional regulators including H-NS and Fis have been studied using ChIP-chip. However, the higher resolution and dynamic range offered by ChIP-Seq have not been exploited for any bacterial species. By performing ChIP-Seq of these two proteins, we present the first such study in a bacterium. In addition to providing a proof-of-principle for the use of this technology for bacteria, we perform our study at multiple time-points during growth in rich medium, thus generating new insights into how these proteins function under different cellular conditions. Further, by analysing our data in conjunction with newly-generated gene expression and RNA polymerase-chromosome interaction data we provide new interpretation of the genome-scale patterns of the interactions of these proteins to the DNA.
2010-09-01 | E-MTAB-332 | biostudies-arrayexpress