Project description:We have studied the transcriptome of S. aureus SH1000 strain, isogenic Teg49 mutant strain, and isogenic plasmid complemented strain
Project description: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 ≤ 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.
Project description:Methicillin-resistant Staphylococcus aureus (MRSA) infections result in more than 200,000 hospitalizations and 10,000 deaths in the United States each year and remain an important medical challenge. To better understand the transcriptome of Staphylococcus aureus USA300 NRS384, a community-acquired MRSA strain, we have conducted an RNA-Seq experiment on WT samples.
Project description:The purpose of this study was to compare the global, growth phase-dependent transcriptional profiles of two isolates of Staphylococcus aureus. One isolate is a prototypic laboratory strain named RN6390, and has been used frequently as a model organism for study of staphylococcal physiology and virulence. However, recent studies indicate that RN6390 is not, in general, genotypically or phenotypically representative of clinical isolates of Staphyloccos aureus. Therefore, there is no current comprehensive picture of gene expression patterns in a virulent, clinical isolate of Staphyloccous aureus. For these reasons, we compare the transcriptional profile of RN6390 to that of a virulent clinical isolate, UAMS-1. Also included in this study is profiling of two UAMS-1 regulatory mutants, UAMS-155, and UAMS-929. These strains possess mutations in the accessory gene regulator (agr) and staphylococcal accessory regulator (sarA) genes, respectively. These two genes are well described global regulatory molecules that are reported to play important roles in controlling virulence factor production and biofilm formation in Staphylococcus aureus. However, most study of these two molecules has been limited to laboratory strains such as RN6390. For these reasons, this study also includes transcriptional profiling of UAMS agr and sarA mutants. Keywords: Comparative, growth phase-dependent transcriptional profiling of bacterial strains and isogenic regulatory mutants
