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
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Mentions: To investigate the discrepancies in the results, we designed a series of nested transcriptional fusion reporter constructs that spanned various regions upstream of pslA. The representative constructs are displayed in Fig. 2A. As shown in Fig. 2B, the reporters containing the promoter region from our study (TR1→DN1 and TR1→DN3) had significantly higher transcriptional activity compared with the reporter containing only the promoter reported in the Overhage study (TR2→DN1 and TR5→DN1). While it is possible that psl has two distinct promoters, we conclude that the majority of the psl transcripts initiate at 148 bp upstream of pslA ORF (designated as +1 in this paper).
Affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.