title: The Salmonella enterica serovar Typhi Vi capsule and self-association pili share controls on expression.
abstract: Salmonella enterica serovar Typhi uses type IVB pili to facilitate eukaryotic cell invasion. Here, we compare environmental and genetic controls on pil operon transcription with those regulating viaB genes required for Vi antigen expression. Transcription of pil occurs only in the late logarithmic and stationary phases of bacterial growth while viaB expression occurs in the logarithmic growth phase. Expression of both viaB and pil was, however, optimal at 100 mM NaCl, and mutations in envZ/ompR, rcsB/rcsC, (but not rcsA), tviA, ihfB or fis affected transcription of both viaB and pil DNA. As both Vi antigen and Type IVB pili facilitate serovar Typhi invasion of human monocytes, an overlap of production controls is logical. It appears that Vi antigen synthesis precedes pilus production.
authors.affiliation: Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Francesca K M
authors.initials: FK
authors.lastname: Lee
authors.forename: Christina
authors.initials: C
authors.lastname: Morris
authors.forename: Jim
authors.initials: J
authors.lastname: Hackett
mesh_terms: D000942:Antigens, Bacterial / Q000096:biosynthesis*; D016667:Bacterial Capsules / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D010861:Fimbriae, Bacterial / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005798:Genes, Bacterial; D009154:Mutation; D009995:Osmosis / Q000502:physiology; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D012485:Salmonella typhi / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity*; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D011135:Polysaccharides, Bacterial; D012965:Sodium Chloride