Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Transcriptome analysis of the WalKR regulon in Staphylococcus aureus

ABSTRACT: The WalKR regulon was studied by comparing genes expression in a strain producing a constitutively active WalR regulator (WalRc) versus the wild type strain carrying the empty expression vector. Hybridizations were performed with three independent biological replicates. Our data allowed to identify 165 genes differentially expressed in the walRc expressing strain with a P-value M-bM-^IM-$ 0.05 using Z-test and a threshold value of two-fold change in transcriptional levels. Among them, 108 genes are activated, and 57 genes are repressed. About 10% of these results were confirmed by quantitative real time PCR, revealing the high reliability of this overall study. Beyond the major effect of the WalKR system on genes expressing cell wall hydrolases, we have shown that it activates a large number of genes involved in virulence, and probably through its positive impact on the SaeRS two-component system, is a major activator of S. aureus virulence. Cells were grown in TSB rich medium added with 0.25 M-BM-5M CdCl2 to allow walRc expression until OD600nm of 1. Gene expression was compared between the HG001 wild type reference strain carrying the pCN51 empty vector (HG001/pCN51) and the HG001 strain carrying a pCN51 derivative with the walRc allele under the control of the Pcad inducible promoter (HG001/pSD3-12). Each condition was done in triplicate and the data were analyzed using the Arraystat software. Genes were considered as differentially expressed if their transcriptional level differed by at least two-fold with a Z-test P-value M-bM-^IM-$ 0.05 in at least two of the replicates.

ORGANISM(S): Staphylococcus aureus

SUBMITTER: Ulrike MM-CM-$der

PROVIDER: E-GEOD-29337 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

The WalKR system controls major staphylococcal virulence genes and is involved in triggering the host inflammatory response.

Delauné Aurélia A Dubrac Sarah S Blanchet Charlène C Poupel Olivier O Mäder Ulrike U Hiron Aurélia A Leduc Aurélie A Fitting Catherine C Nicolas Pierre P Cavaillon Jean-Marc JM Adib-Conquy Minou M Msadek Tarek T

Infection and immunity 20120723 10

The WalKR two-component system is essential for the viability of Staphylococcus aureus, playing a central role in controlling cell wall metabolism. We produced a constitutively active form of WalR in S. aureus through a phosphomimetic amino acid replacement (WalR(c), D55E). The strain displayed significantly increased biofilm formation and alpha-hemolytic activity. Transcriptome analysis was used to determine the full extent of the WalKR regulon, revealing positive regulation of major virulence ...[more]

PMID: 22825451

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Project description:Listeria monocytogenes is able to efficiently utilize glycerol as carbon source. In a defined minimal medium the growth rate is similar (during balanced growth) in presence of glycerol as in presence of glucose or cellobiose. Comparative transcriptome analyses of L. monocytogenes showed in the presence of glycerol (compared to glucose and/or cellobiose) high transcriptional upregulation of the known genes involved in glycerol uptake and metabolism (glpFK, glpD). Expression of the genes encoding a second putative glycerol uptake facilitator (GlpF-2) and a second putative glycerol kinase (GlpK-2) was less enhanced under these conditions. GlpK-1 but not GlpK-2 was essential for glycerol catabolism in L. monocytogenes under extracellular conditions, while loss of GlpK-1 affected replication in Caco-2 cells less than loss of GlpK-2 and GlpD. Additional genes whose transcription was higher in presence of glycerol than in presence of glucose and cellobiose included those for two dihydroxyacetone (Dha) kinases and many genes that are under carbon catabolite repression (CCR) control. Transcriptional down-regulation in the presence of glycerol (compared to glucose and cellobiose) was observed for several genes and operons that are positively regulated by glucose, including genes involved in glycolysis, N-metabolism and biosynthesis of branched chain amino acids. The highest transcriptional up-regulation was observed for all PrfA-dependent genes during early and late logarithmic growth in glycerol. Under these conditions a low level of HPr-Ser-P and a high level of HPr-His-P was present in the cells, suggesting that all EIIA (B) components of the PTS permeases expressed will be phosphorylated. These and other data reported suggest that the phosphorylation state of PTS permeases correlates with PrfA activity. Keywords: Response of Listeria monocytogenes to different carbon sources A total of four independently isolated RNA samples from each condition at each growth phase were used for the analysis. RNA from two isolations were pooled and hybridized onto two microarray slides with dye swap. Another two microarray slides were hybridized using the same principle. In total, we used four RNAs and four microarray slides to generate 16 replicate expression values for each combination except for the comparison between glucose and cellobiose, phase B where data generated from three microarray slides were used for further analysis

Dataset Information

Transcriptome analysis of the WalKR regulon in Staphylococcus aureus

Publications

The WalKR system controls major staphylococcal virulence genes and is involved in triggering the host inflammatory response.

Similar Datasets

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