title: A genomewide mutagenesis screen identifies multiple genes contributing to Vi capsular expression in Salmonella enterica serovar Typhi.
abstract: A transposon-based, genomewide mutagenesis screen exploiting the killing activity of a lytic ViII bacteriophage was used to identify Salmonella enterica serovar Typhi genes that contribute to Vi polysaccharide capsule expression. Genes enriched in the screen included those within the viaB locus (tviABCDE and vexABCDE) as well as oxyR, barA/sirA, and yrfF, which have not previously been associated with Vi expression. The role of these genes in Vi expression was confirmed by constructing defined null mutant derivatives of S. Typhi, and these were negative for Vi expression as determined by agglutination assays with Vi-specific sera or susceptibility to Vi-targeting bacteriophages. Transcriptome analysis confirmed a reduction in expression from the viaB locus in these S. Typhi mutant derivatives and defined regulatory networks associated with Vi expression.
authors: The Wellcome Trust Sanger Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom.
authors: Derek
authors: D
authors: Pickard
authors: Robert A
authors: RA
authors: Kingsley
authors: Christine
authors: C
authors: Hale
authors: Keith
authors: K
authors: Turner
authors: Karthikeyan
authors: K
authors: Sivaraman
authors: Michael
authors: M
authors: Wetter
authors: Gemma
authors: G
authors: Langridge
authors: Gordon
authors: G
authors: Dougan
mesh_terms: D004251:DNA Transposable Elements / Q000235:genetics; D020869:Gene Expression Profiling; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D016296:Mutagenesis; D009154:Mutation; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D012483:Salmonella Phages / Q000502:physiology; D012485:Salmonella typhi / Q000235:genetics* / Q000378:metabolism*
chemical_list: D004251:DNA Transposable Elements; D011135:Polysaccharides, Bacterial; C054154:capsular polysaccharide, Salmonella