The SigB regulon of Staphylococcus aureus
Ontology highlight
ABSTRACT:
ORGANISM(S): Staphylococcus aureus
PROVIDER: GSE87036 | GEO | 2016/11/14
SECONDARY ACCESSION(S): PRJNA343257
REPOSITORIES: GEO
Similar Datasets
Project description:Background. Infections caused by Staphylococcus aureus are associated with significant morbidity and mortality and are an increasing threat not only in hospital settings. The expression of the staphylococcal virulence factor repertoire is known to be affected by the alternative sigma factor B (SigB). However, its impact during infection still is a matter of debate. Methods. Kidney tissue of controls or mice infected with S. aureus HG001 or its isogenic sigB mutant was analyzed by transcriptome profiling to monitor the host response, and additionally expression of selected S. aureus genes was monitored by RT-qPCR. Results. Direct transcript analysis by RT-qPCR revealed significant SigB activity in all mice infected with the wild type strain (WT), but not in its isogenic sigB mutant (p<0.0001). Despite a clear cut difference in the SigB-dependent transcription pattern of virulence genes (clfA, aur, and hla), the host reaction to infection (either WT or sigB mutant) was almost identical. Conclusions. Despite its significant activity in vivo, loss of SigB did not have an effect on the outcome of infection as well as on murine kidney gene expression pattern. Thus, these data support the role of SigB as virulence modulator rather than being a virulence determinant by itself.
2011-10-24 | GSE28540 | GEO
Project description:Background. Infections caused by Staphylococcus aureus are associated with significant morbidity and mortality and are an increasing threat not only in hospital settings. The expression of the staphylococcal virulence factor repertoire is known to be affected by the alternative sigma factor B (SigB). However, its impact during infection still is a matter of debate. Methods. Kidney tissue of controls or mice infected with S. aureus HG001 or its isogenic sigB mutant was analyzed by transcriptome profiling to monitor the host response, and additionally expression of selected S. aureus genes was monitored by RT-qPCR. Results. Direct transcript analysis by RT-qPCR revealed significant SigB activity in all mice infected with the wild type strain (WT), but not in its isogenic sigB mutant (p<0.0001). Despite a clear cut difference in the SigB-dependent transcription pattern of virulence genes (clfA, aur, and hla), the host reaction to infection (either WT or sigB mutant) was almost identical. Conclusions. Despite its significant activity in vivo, loss of SigB did not have an effect on the outcome of infection as well as on murine kidney gene expression pattern. Thus, these data support the role of SigB as virulence modulator rather than being a virulence determinant by itself. Murine kidney gene expression pattern of 3 groups were compared: 1) after infection with S. aureus HG001 (wild type); 2) after infection with S. aureus HG001 ΔsigB; 3) sham control (injection of physiological saline solution). The infection was performed twice (2 biological replicates), and the array analysis included 4 or 5 mice (independent samples) per group. In total, the study consisted of 24 arrays.
2011-10-23 | E-GEOD-28540 | biostudies-arrayexpress
Project description:Bacillus subtilis is exposed to a wide range of transitory stress and starvation conditions. Here we investigate the expression changes observed in the B. subtilis wild type strain 168 and its isogenic sigB mutant(BSM29) with respect to each stress condition tested.
2012-03-14 | GSE32895 | GEO
Project description:The transcription level of a rex-deficient S. aureus mutant in comparison to its parental strain S. aureus SH1000 was analyzed using DNA microarrays.
2009-12-31 | GSE17128 | GEO
Project description:Transcriptome mapping of Staphylococcus aureus wild type and rnc, pnp and sigB mutants
2010-12-31 | E-MEXP-2778 | biostudies-arrayexpress
Project description:A sigB null (∆sigB) mutant was constructed and analyzed for its phenotypes and transcriptome along with those of the parental RF122 strain. Method: Duplicate samples of rRNA depleted RNA from wild type and mutants were used to study transcriptomes by ion torrent platform.
2018-12-28 | GSE77473 | GEO
Project description:The transcription level of a rex-deficient S. aureus mutant in comparison to its parental strain S. aureus SH1000 was analyzed using DNA microarrays. S. aureus N315 microarrays were purchased from Scienion (Scienion AG, Berlin, Germany) and were produced by spotting 2,338 PCR products of the 2,593 ORFs comprising annotated genome of S. aureus N315 [reference identification: NC_002745] on a glass slide. Each ORF is present in duplicate on the microarray (further details can be found at http://www.scienion.com), cDNA was synthesized from total RNA with the LabelStar Array Kit from QIAGEN using the QIAGEN protocol with slight modifications: Random hexamer primer were used (Invitrogen, Karlsruhe, Germany) and Cy3- and Cy5-dCTP were purchased from Perkin-Elmer (Rodgau - Juegesheim, Germany). As recommended by Scienion, 10 µg RNA from either SH1000 or AK1 were used for cDNA synthesis. After hybridisation for 72 h, the microarrays were washed as recommended by the manufacturer. Data analysis. The hybridized microarrays were scanned with a GenePix 4000B microarray scanner (MDS Analytical Technologies GmbH, Ismaning, Germany). A geometric raster was laid over the resulting microarray picture to distinguish the signals from the background. After localization of single spots, intensities and global background were calculated automatically. The hybridization patterns and intensities were quantitatively analyzed using the Imagene 6 software (BioDiscovery, El Segundo, CA). The replicates were averaged, and the spots identified by Imagene 6 (BioDiscovery) as flawed were omitted. The data set was normalized by application of the LOWESS algorithm. In a next step, the intensity values of all arrays for each time point as well as for all time points combined were used for t tests. Genes with a change of <0.5- or â?¥2.0-fold were characterized as having significantly differing amounts of transcripts based on t tests with a P value cut-off of at least 0.05. Gene functions were assigned to the respective accession numbers and annotations as compiled on DOGAN, a web page for S. aureus N315 (http://www.bio.nite.go.jp/dogan/MicroTop?GENOME_ID=n315G1). The parental strain SH1000 and the Rex deficient mutant AK1 were applied on full-genome microarrays to get a detailed view on the differences in the transcriptional profiles which are caused â?? directly or indirectly â?? by the introduced mutation. More specifically, expression levels were compared at five time points, covering different growth phases. To highlight the general changes in the expression profile between SH1000 and the rex mutant, the microarray data of all five time points were also analyzed in a combined way using standard statistical methods. In further experiments, we focused on those genes, which seemed to flag the general difference between the investigated strains.
2010-05-16 | E-GEOD-17128 | biostudies-arrayexpress
Project description:Background: The Bacillus cereus Sigma B (SigB) dependent general stress response is activated via the two-component RsbKY system, which involves a phosphate transfer from RsbK to RsbY. It has been hypothesized that the Hpr-like phosphocarrier protein (Bc1009) encoded by bc1009 in the SigB gene cluster may play a role in this transfer, thereby acting as a regulator of SigB activation. Alternatively, Bc1009 may be involved in the activation of a subset of SigB regulon members. Results: We first investigated the potential role of bc1009 to act as a SigB regulator but ruled out this possibility as the deletion of bc1009 did not affect the expression of sigB and other SigB gene cluster members. The SigB-dependent functions of Bc1009 were further examined in B. cereus ATCC14579 via comparative proteome profiling (backed up by transcriptomics) of wt, Δbc1009 and ΔsigB deletion mutants under heat stress at 42°C. This revealed 284 proteins displaying SigB-dependent alterations in protein expression levels in heat-stressed cells, including a subgroup of 138 proteins for which alterations were also Bc1009-dependent. Next to proteins with roles in stress defense, newly identified SigB and Bc1009-dependent proteins have roles in cell motility, signal transduction, transcription, cell wall biogenesis, and amino acid transport and metabolism. Analysis of lethal stress survival at 50°C after pre-adaptation at 42°C showed intermediate survival efficacy of Δbc1009 cells, highest survival of wt, and lowest survival of ΔsigB cells, respectively. Additional comparative proteome analysis of non-stressed wt and mutant cells at 30°C revealed 96 proteins with SigB and Bc1009-dependent differences in levels, 51 were also identified under heat stress, and 45 showed significant differential expression at 30°C, including proteins with roles in carbohydrate/ion transport and metabolism. Overlapping functions at 30°C and 42°C included proteins involved in motility, and ΔsigB and Δbc1009 cells showed reduced motility compared to wt cells in swimming assays at both temperatures. Conclusion: our results extend the B. cereus SigB regulon to >300 members, with a novel role of SigB-dependent Bc1009 in the activation of a subregulon of >180 members, conceivably via phosphotransfer-based interactions with other transcriptional regulatory networks.
2023-03-02 | GSE213958 | GEO
Project description:The numerous sigma factors present in Mycobacterium tuberculosis (MTB) are indicative of adaptability to different environmental conditions. In this report we describe the sigma factor B (sigB) regulon and the phenotypes of a MTB sigB mutant strain exposed to different stresses like SDS and Diamide. This experiment set compares expression profiles between H37Rv wild type and H37Rv sigB null mutant as well as under different stress conditions. Both H37Rv wild type and H37Rv sigB null mutants were treated with either 0.05% SDS or 5mM Diamide for 60 min and their expression profiles were compared with untreated wild type or mutant controls.
2009-06-23 | GSE15976 | GEO
Project description:The Gram-positive bacterium Staphylococcus aureus is a leading cause of severe pneumonia. Therefore, we recently investigated the fate of S. aureus upon internalization by human lung epithelial cells. This uncovered three major adaptive responses of the bacteria, involving the SigB and CodY regulons and an upregulation of the S. aureus hibernation-promoting factor (SaHPF). To explore the roles of CodY, SigB and SaHPF in the infection of human lung epithelial cells, we employed derivatives of the community-acquired MRSA strain USA300 with transposon mutations in the respective genes. Interestingly, the investigated codY mutant bacteria displayed a ‘small colony variant’-like phenotype that promotes their intracellular survival and localizes the bacteria to the host cell cytoplasm. Furthermore, our results show that CodY, SigB and saHPF contribute differentially to the different steps in the infectious process, including, host cell adhesion, invasion, intracellular survival and cytotoxicity. Notably, codY or sigB mutant bacteria experienced faster intracellular clearance compared to the parental strain, underscoring the importance of these regulators for intracellular persistence. Furthermore, we show an unprecedented role of SaHPF in human lung epithelial cell infection, including parallel effects of saHPF or SigB deficiency in adhesion and invasion. Altogether, our study focuses attention on the CodY-perceived metabolic state of the bacteria and the SigB-perceived stress in bacterial decision taking during infection. Conversely, our observations indicate important roles for the nutritional status and bacterial stress-inducing conditions in the host for the onset and subsequent course of invasive or chronic staphylococcal lung infection.
2024-09-11 | PXD044962 | Pride