Project description:We performed transcriptome abundance analysis of Salmonella Typhimurium strain SL1344 swap which has been genetically engineered to express the hns open-reading frame from the stpA promoter and the stpA open reading frame from the hns promoter. This strain is designated SL1344(swap). Transcript abundance was compared with that of wild-type SL1344. This comparison was performed to determine the effect of chromosome location of the expression of two related global regulators and how alterations to their expression patterns would impact on their regulons.
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
Project description:We performed transcriptome abundance analysis of Salmonella Typhimurium strain SL1344 swap which has been genetically engineered to express the hns open-reading frame from the stpA promoter and the stpA open reading frame from the hns promoter. This strain is designated SL1344(swap). Transcript abundance was compared with that of wild-type SL1344. This comparison was performed to determine the effect of chromosome location of the expression of two related global regulators and how alterations to their expression patterns would impact on their regulons. Three independent RNA samples were harvested from wild-type SL1344 and SL1344(swap) grown to exponential phase (OD600nm = 0.3) and hybridized to a microarray containing multiple probes for each of the SL1344 open reading frames. Please note that the original raw data file for the 'SL1344_wildtype_BR2' sample is unavailable, however, the 'wildtype SL1344 BR2.gpr' contains the raw data missing only the header information.
Project description:FabR ChIP-chip on Salmonella enterica subsp. enterica serovar Typhimurium SL1344 using anti-Myc antibody against strain with chromosomally 9Myc-tagged FabR (IP samples) and wildtype strain (mock IP samples)
Project description:InvF ChIP-chip on Salmonella enterica serovar Typhimurium SL1344 using anti-Myc antibody against strain with chromosomally 9Myc-tagged InvF (IP samples) and wildtype strain (mock IP samples) Salmonella enterica serovar Typhimurium causes a range of diseases from self-limiting gastroenteritis to life-threatening systemic infections. Its complex infection process is initiated by the invasion of the intestinal epithelial monolayer by means of a type three secretion system. InvF is one of the key regulators governing the invasion of epithelial cells. By mapping the InvF regulon, i.e. locating its direct target genes, the gene network underlying invasion can be further examined, including identifying possible new effector-encoding genes. In order to map the InvF regulon, we performed chromatin immunoprecipitation combined with tiling microarray analysis (ChIP-chip) and compared expression of the identified target genes in an invF mutant and a wildtype strain. In addition, the promoter regions of these target genes were searched for the presence of an InvF recognition site. Finally, a query-driven biclustering method, combined with a microarray compendium containing publically available S. Typhimurium gene expression data, was applied as an in silico validation technique for functional relatedness between newly identified target genes and known invasion genes. As expected, under invasion inducing conditions, InvF activates the expression of invasion chaperone encoding sicA and the effector-encoding genes sopB, sopE, sopE2 and sopA by binding their promoter region. Newly identified InvF targets are steB, encoding a secreted effector, and STM1239. The presence of an InvF recognition site in the promoter regions of these target genes further supports this observation. In addition, the query-driven biclustering method revealed similarities in expression profiles between STM1239 and known InvF regulated invasion genes over a range of experimental conditions. In conclusion, we here deliver the first evidence for direct binding of InvF to the promoter regions of sopA and sopE2, and associate genes encoding a secreted effector (steB) and a putative novel effector (STM1239) with the Salmonella invasion regulator InvF.
Project description:We performed Chromatin Immunoprecipitation (ChIP) and microarray hybridization analysis of CspC binding in Salmonella Typhimurium strain SL1344 which has been genetically engineered to express a 3xFLAG tagged CspC protein.
Project description:InvF ChIP-chip on Salmonella enterica serovar Typhimurium SL1344 using anti-Myc antibody against strain with chromosomally 9Myc-tagged InvF (IP samples) and wildtype strain (mock IP samples) Salmonella enterica serovar Typhimurium causes a range of diseases from self-limiting gastroenteritis to life-threatening systemic infections. Its complex infection process is initiated by the invasion of the intestinal epithelial monolayer by means of a type three secretion system. InvF is one of the key regulators governing the invasion of epithelial cells. By mapping the InvF regulon, i.e. locating its direct target genes, the gene network underlying invasion can be further examined, including identifying possible new effector-encoding genes. In order to map the InvF regulon, we performed chromatin immunoprecipitation combined with tiling microarray analysis (ChIP-chip) and compared expression of the identified target genes in an invF mutant and a wildtype strain. In addition, the promoter regions of these target genes were searched for the presence of an InvF recognition site. Finally, a query-driven biclustering method, combined with a microarray compendium containing publically available S. Typhimurium gene expression data, was applied as an in silico validation technique for functional relatedness between newly identified target genes and known invasion genes. As expected, under invasion inducing conditions, InvF activates the expression of invasion chaperone encoding sicA and the effector-encoding genes sopB, sopE, sopE2 and sopA by binding their promoter region. Newly identified InvF targets are steB, encoding a secreted effector, and STM1239. The presence of an InvF recognition site in the promoter regions of these target genes further supports this observation. In addition, the query-driven biclustering method revealed similarities in expression profiles between STM1239 and known InvF regulated invasion genes over a range of experimental conditions. In conclusion, we here deliver the first evidence for direct binding of InvF to the promoter regions of sopA and sopE2, and associate genes encoding a secreted effector (steB) and a putative novel effector (STM1239) with the Salmonella invasion regulator InvF. Three IP samples (from three biological replicates using anti-Myc antibody against Salmonella Typhimurium SL1344 strain encoding chromosomally 9Myc-tagged InvF) and three control mock IP samples (from three biological replicates using anti-Myc antibody against Salmonella Typhimurium SL1344 wildtype strain) were labeled with Cy5 and hybridized against a common genomic DNA reference, labeled with Cy3, on 6 S. Typhimurium LT2 whole genome tiling arrays
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.