E-GEOD-45695 - Regulation by growth temperature of Pseudomonas aeruginosa quorum-sensing depedent virulence factors production involves two RNA-thermometers
Released on 2 April 2013, last updated on 13 May 2014
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 For the transcriptome analysis, cells were growth in PPGAS media at 25 °C and 37 °C, respectively. Samples were harvested at O.D600 of 1.5. Three biological replicates of each growth condition was used for RNA extraction and hybridization on Affimetrix microarrays.
transcription profiling by array