title: sigmaB and the sigmaB-dependent arlRS and yabJ-spoVG loci affect capsule formation in Staphylococcus aureus.
abstract: The alternative transcription factor sigma(B) of Staphylococcus aureus affects the transcription of the cap gene cluster, required for the synthesis of capsular polysaccharide (CP), although this operon is lacking an apparent sigma(B)-dependent promoter. Regulation of cap expression and CP production in S. aureus strain Newman was shown here to be influenced by sigma(B), the two-component signal transduction regulatory system ArlRS, and the yabJ-spoVG locus to different extents. Inactivation of arlR or deletion of the sigB operon strongly suppressed capA (CP synthesis enzyme A) transcription. Deletion of spoVG had a polar effect on yabJ-spoVG transcription and resulted in a two- to threefold decrease in capA transcription. Interestingly, immunofluorescence showed that CP production was strongly impaired in all three mutants, signaling that the yabJ-spoVG inactivation, despite its only partial effect on capA transcription, abolished capsule formation. trans-Complementation of the DeltaspoVG mutant with yabJ-spoVG under the control of its native promoter restored CP-5 production and capA expression to levels seen in the wild type. Northern analyses revealed a strong impact of sigma(B) on arlRS and yabJ-spoVG transcription. We hypothesize that ArlR and products of the yabJ-spoVG locus may serve as effectors that modulate sigma(B) control over sigma(B)-dependent genes lacking an apparent sigma(B) promoter.
authors.affiliation: Institute of Medical Microbiology, University of Zürich, Gloriastr. 32, 8006 Zürich, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Meier
authors.forename: Christiane
authors.initials: C
authors.lastname: Goerke
authors.forename: Christiane
authors.initials: C
authors.lastname: Wolz
authors.forename: Kati
authors.initials: K
authors.lastname: Seidl
authors.forename: Dagmar
authors.initials: D
authors.lastname: Homerova
authors.forename: Bettina
authors.initials: B
authors.lastname: Schulthess
authors.forename: Jan
authors.initials: J
authors.lastname: Kormanec
authors.forename: Brigitte
authors.initials: B
authors.lastname: Berger-Bächi
authors.forename: Markus
authors.initials: M
authors.lastname: Bischoff
mesh_terms: D016667:Bacterial Capsules / Q000096:biosynthesis / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D005819:Genetic Markers; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis / Q000235:genetics; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000235:genetics*; D012808:Sigma Factor / Q000235:genetics / Q000502:physiology*; D013171:Spores, Bacterial / Q000235:genetics; D013211:Staphylococcus aureus / Q000235:genetics*
chemical_list: C411334:ArlR protein, Staphylococcus aureus; D001426:Bacterial Proteins; D005819:Genetic Markers; D011135:Polysaccharides, Bacterial; C079011:SigB protein, Bacteria; D012808:Sigma Factor; D011494:Protein Kinases; C411333:ArlS protein, Staphylococcus aureus