Negative Control of RpoS Synthesis by the sRNA ReaL in Pseudomonas aeruginosa

Abstract

<i>Pseudomonas aeruginosa</i> (Pae) is an opportunistic human pathogen, able to resist host defense mechanisms and antibiotic treatment. In Pae, the master regulator of stress responses RpoS (σ^S) is involved in the regulation of quorum sensing and several virulence genes. Here, we report that the sRNA ReaL translationally silences <i>rpoS</i> mRNA, which results in a decrease of the RpoS levels. Our studies indicated that ReaL base-pairs with the Shine-Dalgarno region of <i>rpoS</i> mRNA. These studies are underlined by a highly similar transcription profile of a <i>rpoS</i> deletion mutant and a <i>reaL</i> over-expressing strain.