Pseudomonas aeruginosa biofilm matrix polysaccharide Psl is regulated transcriptionally by RpoS and post-transcriptionally by RsmA.
Bottom Line: In this study, we demonstrate that the alternative σ-factor RpoS is a positive transcriptional regulator of psl gene expression.Furthermore, we show that psl mRNA has an extensive 5' untranslated region, to which the post-transcriptional regulator RsmA binds and represses psl translation.This constitutes a novel mechanism for translational repression by this family of regulators.
Affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.Show MeSH
Mentions: Predicted RsmA binding site in the psl 5′ UTR.A. The predicted position of SD is indicated by the underlined 7–12 bases upstream of the start codon of pslA ORF. Predicted RsmA binding site is boxed, 24–37 bases upstream of the start codon. The asterisks indicate the GG nucleotide pair required for CsrA/RsmA binding to its RNA target, which was mutated to the CC pair for the experiments demonstrated in Fig. 11. +1 indicates the transcriptional start site (in bold font) and the corresponding −10 and −35 regions of the promoter (underlined).B. Sequence alignment of psl RsmA binding site with the CsrA consensus sequence (R = A or G) as previously reported (Dubey et al., 2005).
Affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.