title: A tdcA mutation reduces the invasive ability of Salmonella enterica serovar typhimurium.
abstract: We previously observed that the transcription of some flagellar genes decreased in Salmonella Typhimurium tdcA mutant, which is a gene encoding the transcriptional activator of the tdc operon. Since flagella-mediated bacterial motility accelerates the invasion of Salmonella, we have examined the effect of tdcA mutation on the invasive ability as well as the flagellar biosynthesis in S. Typhimurium. A tdcA mutation caused defects in motility and formation of flagellin protein, FliC in S. Typhimurium. Invasion assays in the presence of a centrifugal force confirmed that the defect of flagellum synthesis decreases the ability of Salmonella to invade into cultured epithelial cells. In addition, we also found that the expression of Salmonella pathogenicity island 1 (SPI1) genes required for Salmonella invasion was down-regulated in the tdcA mutant because of the decreased expression of fliZ, a positive regulator of SPI1 transcriptional activator, hilA. Finally, the virulence of a S. Typhimurium tdcA mutant was attenuated compared to a wild type when administered orally. This study implies the role of tdcA in the invasion process of S. Typhimurium.
authors.affiliation: Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea.
authors.forename: Minjeong
authors.initials: M
authors.lastname: Kim
authors.forename: Sangyong
authors.initials: S
authors.lastname: Lim
authors.forename: Dongho
authors.initials: D
authors.lastname: Kim
authors.forename: Hyon E
authors.initials: HE
authors.lastname: Choy
authors.forename: Sangryeol
authors.initials: S
authors.lastname: Ryu
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000382:microbiology; D005407:Flagella / Q000235:genetics / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D009154:Mutation; D012486:Salmonella typhimurium / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics