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Pseudomonas aeruginosa biofilm matrix polysaccharide Psl is regulated transcriptionally by RpoS and post‐transcriptionally by RsmA
Author(s) -
Irie Yasuhiko,
Starkey Melissa,
Edwards Adrianne N.,
Wozniak Daniel J.,
Romeo Tony,
Parsek Matthew R.
Publication year - 2010
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2010.07320.x
Subject(s) - biology , rpos , ribosomal binding site , psl , ribosome , biofilm , psychological repression , regulator , untranslated region , microbiology and biotechnology , messenger rna , transcriptional regulation , start codon , translation (biology) , luciferase , gene , gene expression , genetics , promoter , rna , bacteria , transfection , geometry , mathematics
Summary Extracellular polysaccharides are important components of biofilms. In non‐mucoid Pseudomonas aeruginosa strains, the Pel and Psl polysaccharides are major structural components of the biofilm matrix. 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. Our observations suggest that upon binding RsmA, the region spanning the ribosome binding site of psl mRNA folds into a secondary stem‐loop structure that blocks the Shine–Dalgarno sequence, preventing ribosome access and protein translation. This constitutes a novel mechanism for translational repression by this family of regulators.