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 homolog (PA2582/ProQ _Pae ) in Pseudomonas aeruginosa ( Pae ). To address the function of ProQ _Pae , at first a comparative transcriptome analysis of the Pae strains PAO1 and PAO1Δ proQ was performed. This study 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 ProQ _Pae with these transcripts. In accordance with the up-regulation of the psrA , pprA , and pprB genes in strain PAO1Δ proQ a phenotypic analysis revealed an increased susceptibility toward the aminoglycosides tobramycin and gentamicin in biofilms. Conversely, the observed down-regulation of the oprI gene in PAO1Δ proQ could be reconciled with a decreased susceptibility toward the synthetic cationic antimicrobial peptide GW-Q6. Taken together, these studies revealed that ProQ _Pae is an RBP that impacts antimicrobial resistance in Pae .
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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