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: Translational fusion data showed that psl translation was threefold to fourfold higher in ΔrsmA than WT (Figs 6B and S2B), despite psl transcriptional activity being similar (Figs 6A and S2A). Elevated psl translational activity in ΔrsmA could be complemented by overexpressing RsmA (Fig. 6C). RsmA overexpression further reduced the activity below the WT level, providing additional evidence that RsmA acts as a repressor of psl.
Affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.