Transcriptome analysis of the WalKR regulon in Staphylococcus aureus
Ontology highlight
ABSTRACT:
ORGANISM(S): Staphylococcus aureus subsp. aureus NCTC 8325 Staphylococcus aureus
PROVIDER: GSE29337 | GEO | 2012/09/13
SECONDARY ACCESSION(S): PRJNA140141
REPOSITORIES: GEO
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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 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.
2012-09-13 | E-GEOD-29337 | biostudies-arrayexpress
Project description:WalKR is an essential two component regulatory system in S. aureus, thought to control cell wall metabolism. Using genome sequencing of 5 paired clinical isolates of vancomycin-susceptible and vancomycin-intermediate S. aureus we found frequent, but unique, mutations in this locus. To investigate the contribution of these mutations to vancomycin resistance allelic replacement WalK (G223D) and WalR (K208R) mutants were generated and compared to the parent strains. Mutations in walk and walR led to increased vancomycin resistance, reduced biofilms formation and attenuation of virulence, demonstrating that minor genetic changes in this locus can lead to significant changes in bacterial resistance and virulence. Microarray transcriptional comparisons were performed to investigate the regulatory effects of the WalK (G223D) and WalR (K208R) mutations, and demonstrated that while changes in genes affecting cell wall metabolism were detected, more dramatic changes were found in regulation of cellular metabolism. Transcriptional profiling of laboratory derived S. aureus walKR mutants compared to the parent isolates. TPS3130 has a single point mutation in walK, and TPS3190 has a single point mutation in walR. Two condition experiment TPS3130 vs JKD6009 and TPS3190 vs JKD6004. 3 biological replicates per isolate pair, one replicate per slide.
2012-05-31 | E-GEOD-29157 | biostudies-arrayexpress
Project description:WalKR is an essential two component regulatory system in S. aureus, thought to control cell wall metabolism. Using genome sequencing of 5 paired clinical isolates of vancomycin-susceptible and vancomycin-intermediate S. aureus we found frequent, but unique, mutations in this locus. To investigate the contribution of these mutations to vancomycin resistance allelic replacement WalK (G223D) and WalR (K208R) mutants were generated and compared to the parent strains. Mutations in walk and walR led to increased vancomycin resistance, reduced biofilms formation and attenuation of virulence, demonstrating that minor genetic changes in this locus can lead to significant changes in bacterial resistance and virulence. Microarray transcriptional comparisons were performed to investigate the regulatory effects of the WalK (G223D) and WalR (K208R) mutations, and demonstrated that while changes in genes affecting cell wall metabolism were detected, more dramatic changes were found in regulation of cellular metabolism.
2012-06-01 | GSE29157 | GEO
Project description:Here, we use a panel of defined walKR mutants and functional genomics including ChIP-seq to confirm a high-resolution consensus WalR DNA-binding motif and characterise a 61-gene direct regulon
2022-09-01 | GSE212319 | GEO
Project description:Here, we use a panel of defined walKR mutants and functional genomics including ChIP-seq to confirm a high-resolution consensus WalR DNA-binding motif and characterise a 61-gene direct regulon
2022-09-01 | GSE212318 | GEO
Project description:Background: Staphylococcus epidermidis (SE) has emerged as one of the most important causes of nosocomial infections. The SaeRS two-component signal transduction system (TCS) influences virulence and biofilm formation in Staphylococcus aureus. The deletion of saeR in S. epidermidis results in impaired anaerobic growth and decreased nitrate utilization. However, the regulatory function of SaeRS on biofilm formation and autolysis in S. epidermidis remains unclear. Results: The saeRS genes of SE1457 were deleted by homologous recombination. The saeRS deletion mutant, SE1457DsaeRS, exhibited increased biofilm formation that was disturbed more severely (a 4-fold reduction) by DNase I treatment compared to SE1457 and the complementation strain SE1457saec. Compared to SE1457 and SE1457saec, SE1457DsaeRS showed increased Triton X-100-induced autolysis (approximately 3-fold) and decreased cell viability in planktonic/biofilm states; further, SE1457DsaeRS also released more extracellular DNA (eDNA) in the biofilms. Correlated with the increased autolysis phenotype, the transcription of autolysis-related genes, such as atlE and aae, was increased in SE1457DsaeRS. Whereas the expression of accumulation-associated protein was up-regulated by 1.8-fold in 1457DsaeRS, the expression of an N-acetylglucosaminyl transferase enzyme (encoded by icaA) critical for polysaccharide intercellular adhesion (PIA) synthesis was not affected by the deletion of saeRS. Conclusions: Deletion of saeRS in S. epidermidis resulted in an increase in biofilm-forming ability, which was associated with increased eDNA release and up-regulated Aap expression. The increased eDNA release from SE1457DsaeRS was associated with increased bacterial autolysis and decreased bacterial cell viability in the planktonic/biofilm states. Comparision between SE1457 wild type strain and SA1457 SaeRS mutant strain after 4 hours and 12 hours of growth
2012-01-12 | E-GEOD-29309 | biostudies-arrayexpress
Project description:Staphylococcus aureus is a Gram-positive opportunistic pathogen, which is carried by approximately 30 % of the population at any time. In addition to being a commensal S. aureus can cause an array of infections, ranging from mild skin and soft tissue infections to life threatening endocarditis and septicemia. S. aureus encodes a variety of virulence factors that facilitate its pathogenic lifestyle. Genes encoding these virulence factors are under tight control by a complex regulatory network, which includes, sigma factors, sRNAs, and protein-based systems, such as Two-Component Systems (TCS). Previous work in our lab demonstrated that overexpression of the sRNA tsr37 leads to an increase in cellular aggregation in the absence of host serum. We determined that the clumping phenotype was dependent on a previously unannotated 88 amino acid protein encoded within the tsr37 sRNA transcript (which we named ScrA for S. aureus clumping regulator A). In addition to increased clumping, overexpression of ScrA also leads to increased biofilm formation. To investigate the mechanism of action of ScrA we performed mass spectrometry proteomics and RNA-sequencing in the ScrA overexpressing strain. A variety of virulence factors, including several surface adhesins were upregulated while several proteases were downregulated. Moreover, results showed a significant upregulation of the SaeRS two component system, suggesting that ScrA is influencing SaeRS activity. We go on to demonstrate that overexpression of ScrA in a saeR mutant abrogates the clumping/biofilm phenotypes confirming that ScrA functions via the Sae system. Finally, we identified the ArlRS TCS as a potential positive regulator of scrA expression. Collectively our results show that ScrA is an activator of the SaeRS system and suggests that ScrA may act as an intermediary between the ArlRS and SaeRS systems.
2022-08-11 | PXD028409 | Pride
Project description:Background: Staphylococcus epidermidis (SE) has emerged as one of the most important causes of nosocomial infections. The SaeRS two-component signal transduction system (TCS) influences virulence and biofilm formation in Staphylococcus aureus. The deletion of saeR in S. epidermidis results in impaired anaerobic growth and decreased nitrate utilization. However, the regulatory function of SaeRS on biofilm formation and autolysis in S. epidermidis remains unclear. Results: The saeRS genes of SE1457 were deleted by homologous recombination. The saeRS deletion mutant, SE1457DsaeRS, exhibited increased biofilm formation that was disturbed more severely (a 4-fold reduction) by DNase I treatment compared to SE1457 and the complementation strain SE1457saec. Compared to SE1457 and SE1457saec, SE1457DsaeRS showed increased Triton X-100-induced autolysis (approximately 3-fold) and decreased cell viability in planktonic/biofilm states; further, SE1457DsaeRS also released more extracellular DNA (eDNA) in the biofilms. Correlated with the increased autolysis phenotype, the transcription of autolysis-related genes, such as atlE and aae, was increased in SE1457DsaeRS. Whereas the expression of accumulation-associated protein was up-regulated by 1.8-fold in 1457DsaeRS, the expression of an N-acetylglucosaminyl transferase enzyme (encoded by icaA) critical for polysaccharide intercellular adhesion (PIA) synthesis was not affected by the deletion of saeRS. Conclusions: Deletion of saeRS in S. epidermidis resulted in an increase in biofilm-forming ability, which was associated with increased eDNA release and up-regulated Aap expression. The increased eDNA release from SE1457DsaeRS was associated with increased bacterial autolysis and decreased bacterial cell viability in the planktonic/biofilm states.
2012-01-12 | GSE29309 | GEO
Project description:Streptococcus agalactiae (Group B Streptococcus, GBS) can colonize the human vaginal tract leading to both superficial and serious infections in adults and neonates. To study bacterial colonization of the reproductive tract in a mammalian system, we employed a murine vaginal carriage model. Using RNASeq, the transcriptome of GBS growing in vivo during vaginal carriage was determined. Over one-quarter of the genes in GBS were found to be differentially regulated during in vivo colonization as compared to laboratory cultures. A two-component system (TCS) homologous to the staphylococcal virulence regulator SaeRS was identified as being up-regulated in vivo. One of the SaeRS targets, pbsP, a proposed GBS vaccine candidate, was shown to be important for colonization of the vaginal tract. A component of vaginal lavage fluid acted as a signal to turn on pbsP expression via SaeRS. These data demonstrate the ability to quantify RNA expression directly from the murine vaginal tract and identify novel genes involved in vaginal colonization by GBS. They also provide more information about the regulation of an important virulence and colonization factor of GBS, pbsP, by the TCS SaeRS.
2018-02-06 | GSE109680 | GEO
Project description:Staphylococcus aureus is a Gram-positive opportunistic pathogen, which is carried by approximately 30 % of the population at any time. In addition to being a commensal S. aureus can cause an array of infections, ranging from mild skin and soft tissue infections to life threatening endocarditis and septicemia. S. aureus encodes a variety of virulence factors that facilitate its pathogenic lifestyle. Genes encoding these virulence factors are under tight control by a complex regulatory network, which includes, sigma factors, sRNAs, and protein-based systems, such as Two-Component Systems (TCS). Previous work in our lab demonstrated that overexpression of the sRNA tsr37 leads to an increase in cellular aggregation in the absence of host serum. We determined that the clumping phenotype was dependent on a previously unannotated 88 amino acid protein encoded within the tsr37 sRNA transcript (which we named ScrA for S. aureus clumping regulator A). In addition to increased clumping, overexpression of ScrA also leads to increased biofilm formation. To investigate the mechanism of action of ScrA we performed mass spectrometry proteomics and RNA-sequencing in the ScrA overexpressing strain. A variety of virulence factors, including several surface adhesins were upregulated while several proteases were downregulated. Moreover, results showed a significant upregulation of the SaeRS two component system, suggesting that ScrA is influencing SaeRS activity. We go on to demonstrate that overexpression of ScrA in a saeR mutant abrogates the clumping/biofilm phenotypes confirming that ScrA functions via the Sae system. Finally, we identified the ArlRS TCS as a potential positive regulator of scrA expression. Collectively our results show that ScrA is an activator of the SaeRS system and suggests that ScrA may act as an intermediary between the ArlRS and SaeRS systems.
2021-10-01 | GSE184753 | GEO