The FinO/ProQ-like protein PA2582 impacts antimicrobial resistance in Pseudomonas aeruginosa
Bacteria employ small regulatory RNAs (sRNA) and/or RNA binding proteins (RBPs) to respond to environmental cues. In Enterobacteriaceae, the FinO-domain containing RBP ProQ associates with numerous sRNAs and mRNAs, impacts sRNA-mediated riboregulation or mRNA stability by binding to 5'- or 3'-untranslated regions as well as to internal stem loop structures. Global RNA-protein interaction studies and sequence comparisons identified a ProQ-like homologue (PA2582) in Pseudomonas aeruginosa (Pae). A comparative transcriptome analyses of the Pae strains PAO1 and PAO1?proQ revealed more than 100 differentially abundant transcripts, affecting a variety of cellular functions. Among these transcripts were pprA and pprB, encoding the PprA/PprB two component system, psrA, encoding a transcriptional activator of pprB, and oprI, encoding the outer membrane protein OprI. RNA co-purification experiments with Strep-tagged Pae ProQ protein corroborated an association of ProQPae with these transcripts. In accordance with the up-regulation of the psrA, pprA and pprB genes in strain PAO1?proQ, a phenotypic analysis revealed an increased susceptibility towards aminoglycoside antibiotics in biofilms. Conversely, the observed down-regulation of the oprI gene in PAO1?proQ could be reconciled with a decreased susceptibility towards the antimicrobial peptide GW-Q6.