title: Positive control of swarming, rhamnolipid synthesis, and lipase production by the posttranscriptional RsmA/RsmZ system in Pseudomonas aeruginosa PAO1.
abstract: In Pseudomonas aeruginosa, the small RNA-binding, regulatory protein RsmA is a negative control element in the formation of several extracellular products (e.g., pyocyanin, hydrogen cyanide, PA-IL lectin) as well as in the production of N-acylhomoserine lactone quorum-sensing signal molecules. RsmA was found to control positively the ability to swarm and to produce extracellular rhamnolipids and lipase, i.e., functions contributing to niche colonization by P. aeruginosa. An rsmA null mutant was entirely devoid of swarming but produced detectable amounts of rhamnolipids, suggesting that factors in addition to rhamnolipids influence the swarming ability of P. aeruginosa. A small regulatory RNA, rsmZ, which antagonized the effects of RsmA, was identified in P. aeruginosa. Expression of the rsmZ gene was dependent on both the global regulator GacA and RsmA, increased with cell density, and was subject to negative autoregulation. Overexpression of rsmZ and a null mutation in rsmA resulted in quantitatively similar, negative or positive effects on target genes, in agreement with a model that postulates titration of RsmA protein by RsmZ RNA.
authors.affiliation: Institut de Microbiologie Fondamentale, Université de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Karin
authors.initials: K
authors.lastname: Heurlier
authors.forename: Faye
authors.initials: F
authors.lastname: Williams
authors.forename: Stephan
authors.initials: S
authors.lastname: Heeb
authors.forename: Corinne
authors.initials: C
authors.lastname: Dormond
authors.forename: Gabriella
authors.initials: G
authors.lastname: Pessi
authors.forename: Dustin
authors.initials: D
authors.lastname: Singer
authors.forename: Miguel
authors.initials: M
authors.lastname: Cámara
authors.forename: Paul
authors.initials: P
authors.lastname: Williams
authors.forename: Dieter
authors.initials: D
authors.lastname: Haas
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D001483:Base Sequence; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D006017:Glycolipids / Q000096:biosynthesis*; D008049:Lipase / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism*; D012329:RNA, Bacterial / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D006017:Glycolipids; D012329:RNA, Bacterial; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C095468:RsmA protein, Erwinia carotovora; C418382:rhamnolipid; D008049:Lipase