A Distinct QscR Regulon in the Pseudomonas aeruginosa Quorum Sensing Circuit
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ABSTRACT:
ORGANISM(S): Pseudomonas aeruginosa
PROVIDER: GSE4026 | GEO | 2006/01/18
SECONDARY ACCESSION(S): PRJNA95131
REPOSITORIES: GEO
Similar Datasets
Project description:To better understand the role of QscR in P. aeruginosa gene regulation and to better understand the relationship between QscR, LasR and RhlR control of gene expression we used transcription profiling to identify a QscR-dependent regulon. Our analysis revealed that QscR activates some genes and represses others. Some of the repressed genes are not regulated by the LasR-I or RhlR-I systems while others are. The LasI-generated 3-oxododecanoyl-homoserine lactone serves as a signal molecule for QscR. Thus QscR appears to be an integral component of the P. aeruginosa quorum sensing circuitry. QscR uses the LasI-generated acyl-homoserine lactone signal and controls a specific regulon that overlaps with the already overlapping LasR and RhlR-dependent regulons. Experiment Overall Design: First comparisaon Experiment Overall Design: We first compared transcriptomes of the qscR mutant P. aeruginosa PAO-R3 and the parental strain PAO1 at several points during growth (OD600nm 0.5, 0.8, 1.4, 2.0 and 3.5). To identify those genes with expression significantly different between PAO1 and PAO-R3 at different culture densities we used CYBER-T. The Bayesian prior estimate was 10 and the sliding window size was 101. The p-value threshold was 0.001, the posterior probability of differential expression >0.95, and fold change was >2.5. Experiment Overall Design: Second comparison Experiment Overall Design: We selected genes that were at least 3-fold differentially expressed in the strain containing the L-arabinose promoter-driven qscR allele vs the strain containing L-arabinose promoter-driven qscR-Ddbd allele, and were also at least 3-fold differentially expressed in the parent strain PAO1 as compared to the strain containing the qscR null mutation. RNA were extracted from cultures at OD 0.5, 0.8, 1.4, 2.0 and 3.5
2008-06-12 | E-GEOD-4026 | biostudies-arrayexpress
Project description:Quorum sensing controls the expression of multiple virulence factors. PA14 genes lasR and rhlR are necessary for quorum sensing via homoserine lactones. A PA14 lasR rhlR deficient mutant exhibits a reduced oxidative stress response. Here we conducted a microarray to determine oxidative stress response gene regulation mediated by the homoserine lactone quorum sensing circuits. A PA14 lasR rhlR deficient mutant was compared to the wild-type with and without H2O2 stress.
2015-01-09 | E-GEOD-54245 | biostudies-arrayexpress
Project description:Quorum sensing controls the expression of multiple virulence factors. PA14 genes lasR and rhlR are necessary for quorum sensing via homoserine lactones. A PA14 lasR rhlR deficient mutant exhibits a reduced oxidative stress response. Here we conducted a microarray to determine oxidative stress response gene regulation mediated by the homoserine lactone quorum sensing circuits.
2015-01-09 | GSE54245 | GEO
Project description:In people with the genetic disease cystic fibrosis (CF), bacterial infections involving the opportunistic pathogen Pseudomonas aeruginosa are a significant cause of morbidity and mortality. P. aeruginosa uses a cell-cell signaling mechanism called quorum sensing (QS) to regulate many virulence functions. One type of QS consists of acyl-homoserine lactone (AHL) signals produced by LuxI-type signal synthases, which bind a cognate LuxR-type transcription factor. In laboratory strains and conditions, P. aeruginosa employs two AHL synthase/receptor pairs arranged in a hierarchy, with the LasI/R system controlling the RhlI/R system and many downstream virulence factors. However, P. aeruginosa isolates with inactivating mutations in lasR are frequently isolated from chronic CF infections. We and others have shown that these isolates frequently use RhlR as the primary QS regulator. RhlR is rarely mutated in CF and environmental settings. We were interested if there were reproducible genetic characteristics of these isolates and if there was a central group of genes regulated by RhlR in all isolates. We examined five isolates and found signatures of adaptation common to CF isolates. Here, we analyzed CF clinial isolate E125. In this strain, RhlR positively regulates 28 genes, including those coding for known virulence factors. These results suggest a key group of QS-regulated factors important for pathogenesis of chronic infection, and position RhlR as a target for anti-QS therapeutics. Our work underscores the need to sample a diversity of isolates to understanding QS beyond what has been described in laboratory strains.
2022-03-18 | GSE198717 | GEO
Project description:In people with the genetic disease cystic fibrosis (CF), bacterial infections involving the opportunistic pathogen Pseudomonas aeruginosa are a significant cause of morbidity and mortality. P. aeruginosa uses a cell-cell signaling mechanism called quorum sensing (QS) to regulate many virulence functions. One type of QS consists of acyl-homoserine lactone (AHL) signals produced by LuxI-type signal synthases, which bind a cognate LuxR-type transcription factor. In laboratory strains and conditions, P. aeruginosa employs two AHL synthase/receptor pairs arranged in a hierarchy, with the LasI/R system controlling the RhlI/R system and many downstream virulence factors. However, P. aeruginosa isolates with inactivating mutations in lasR are frequently isolated from chronic CF infections. We and others have shown that these isolates frequently use RhlR as the primary QS regulator. RhlR is rarely mutated in CF and environmental settings. We were interested if there were reproducible genetic characteristics of these isolates and if there was a central group of genes regulated by RhlR in all isolates. We examined five isolates and found signatures of adaptation common to CF isolates. Here, we analyzed CF clinial isolate E167. In this strain, RhlR positively regulates 78 genes, including those coding for known virulence factors. These results suggest a key group of QS-regulated factors important for pathogenesis of chronic infection, and position RhlR as a target for anti-QS therapeutics. Our work underscores the need to sample a diversity of isolates to understanding QS beyond what has been described in laboratory strains.
2022-03-18 | GSE198719 | GEO
Project description:In people with the genetic disease cystic fibrosis (CF), bacterial infections involving the opportunistic pathogen Pseudomonas aeruginosa are a significant cause of morbidity and mortality. P. aeruginosa uses a cell-cell signaling mechanism called quorum sensing (QS) to regulate many virulence functions. One type of QS consists of acyl-homoserine lactone (AHL) signals produced by LuxI-type signal synthases, which bind a cognate LuxR-type transcription factor. In laboratory strains and conditions, P. aeruginosa employs two AHL synthase/receptor pairs arranged in a hierarchy, with the LasI/R system controlling the RhlI/R system and many downstream virulence factors. However, P. aeruginosa isolates with inactivating mutations in lasR are frequently isolated from chronic CF infections. We and others have shown that these isolates frequently use RhlR as the primary QS regulator. RhlR is rarely mutated in CF and environmental settings. We were interested if there were reproducible genetic characteristics of these isolates and if there was a central group of genes regulated by RhlR in all isolates. We examined five isolates and found signatures of adaptation common to CF isolates. Here, we analyzed CF clinial isolate E131. In this strain, RhlR positively regulates 105 genes, including those coding for known virulence factors. These results suggest a key group of QS-regulated factors important for pathogenesis of chronic infection, and position RhlR as a target for anti-QS therapeutics. Our work underscores the need to sample a diversity of isolates to understanding QS beyond what has been described in laboratory strains.
2022-03-18 | GSE198718 | GEO
Project description:In people with the genetic disease cystic fibrosis (CF), bacterial infections involving the opportunistic pathogen Pseudomonas aeruginosa are a significant cause of morbidity and mortality. P. aeruginosa uses a cell-cell signaling mechanism called quorum sensing (QS) to regulate many virulence functions. One type of QS consists of acyl-homoserine lactone (AHL) signals produced by LuxI-type signal synthases, which bind a cognate LuxR-type transcription factor. In laboratory strains and conditions, P. aeruginosa employs two AHL synthase/receptor pairs arranged in a hierarchy, with the LasI/R system controlling the RhlI/R system and many downstream virulence factors. However, P. aeruginosa isolates with inactivating mutations in lasR are frequently isolated from chronic CF infections. We and others have shown that these isolates frequently use RhlR as the primary QS regulator. RhlR is rarely mutated in CF and environmental settings. We were interested if there were reproducible genetic characteristics of these isolates and if there was a central group of genes regulated by RhlR in all isolates. We examined five isolates and found signatures of adaptation common to CF isolates. Here, we analyzed CF clinial isolate E104. In this strain, RhlR positively regulates 48 genes, including those coding for known virulence factors. These results suggest a key group of QS-regulated factors important for pathogenesis of chronic infection, and position RhlR as a target for anti-QS therapeutics. Our work underscores the need to sample a diversity of isolates to understanding QS beyond what has been described in laboratory strains.
2022-03-18 | GSE198534 | GEO
Project description:In people with the genetic disease cystic fibrosis (CF), bacterial infections involving the opportunistic pathogen Pseudomonas aeruginosa are a significant cause of morbidity and mortality. P. aeruginosa uses a cell-cell signaling mechanism called quorum sensing (QS) to regulate many virulence functions. One type of QS consists of acyl-homoserine lactone (AHL) signals produced by LuxI-type signal synthases, which bind a cognate LuxR-type transcription factor. In laboratory strains and conditions, P. aeruginosa employs two AHL synthase/receptor pairs arranged in a hierarchy, with the LasI/R system controlling the RhlI/R system and many downstream virulence factors. However, P. aeruginosa isolates with inactivating mutations in lasR are frequently isolated from chronic CF infections. We and others have shown that these isolates frequently use RhlR as the primary QS regulator. RhlR is rarely mutated in CF and environmental settings. We were interested if there were reproducible genetic characteristics of these isolates and if there was a central group of genes regulated by RhlR in all isolates. We examined five isolates and found signatures of adaptation common to CF isolates. Here, we analyzed CF clinial isolate E113. In this strain, RhlR positively regulates 186 genes, including those coding for known virulence factors. These results suggest a key group of QS-regulated factors important for pathogenesis of chronic infection, and position RhlR as a target for anti-QS therapeutics. Our work underscores the need to sample a diversity of isolates to understanding QS beyond what has been described in laboratory strains.
2022-03-18 | GSE198716 | GEO
Project description:The opportunistic pathogen Pseudomonas aeruginosa has complex quorum sensing (QS) circuitry, which involves two acylhomoserine lactone (AHL) systems, the LasI AHL synthase and LasR AHL-dependent transcriptional activator system and the RhlI AHL synthase-RhlR AHL-responsive transcriptional activator. There is also a quinoline signaling system (the Pseudomonas quinolone signal, PQS, system). Although there is a core set of genes regulated by the AHL circuits, there is substantial strain-to-strain variation in the non-core QS regulated genes. Reductive evolution of the QS regulon, and variation in specific genes activated by QS occurs in laboratory evolution experiments with the model strain PAO1. We used a transcriptomics approach to test the hypothesis that reductive evolution in the PAO1 QS regulon can in large part be explained by a simple null mutation in pqsR, the gene encoding the transcriptional activator of the pqs operon. We found that PqsR had very little influence on the AHL QS regulon. This was a surprising finding because the last gene in the PqsR-dependent pqs operon, pqsE, codes for a protein, which physically interacts with RhlR and this interaction is required for full RhlR-dependent activation of some genes. We used comparative transcriptomics to examine the influence of a pqsE mutation on the QS regulon and identified only three transcripts, which were strictly dependent on PqsE. By using reporter constructs we showed that the PqsE influence on other genes was dependent on experimental conditions and we have gained some insight about those conditions. This work adds to our understanding of the plasticity of the P. aeruginosa QS regulon and to the role PqsE plays in RhlR-dependent gene activation.
2024-03-17 | GSE261453 | GEO
Project description:Several bacterial human pathogens regulate the production of virulence factors by temperature, expressing them only at 37 °C. Accordingly we show that the production of all P. aeruginosa virulence factors that are dependent on the QS transcriptional regulator RhlR, but only a fraction that are activated by LasR, are induced at 37 °C compared to 30 °C or 25 °C. The RhlR-dependent induction at 37 °C is a posttranscriptional effect due to an RNA thermometer of the ROSE family that thermoregulates the expression of rhlAB operon involved in rhamnolipids production, a virulence associated trait. This RNA structure also affects the expression of the downstream rhlR gene. A second thermometer is present upstream lasI and causes a reduced expression of this gene at lower temperatures without causing a significant decrease of the autoinducer 3-oxo-dodecanoyl homoserine lactone. Using transcriptomic analysis and quantitative real time PCR we show that these RNA thermometers are the main mechanism of thermoregulation of P. aeruginosa virulence factor production
2013-04-02 | GSE45695 | GEO