title: Regulation and production of Tcf, a cable-like fimbriae from Salmonella enterica serovar Typhi.
abstract: tcf (Typhi colonization factor) is one of the 12 putative chaperone/usher fimbrial clusters present in the Salmonella enterica serovar Typhi genome. We investigated the production, expression and regulation of tcf as well as its role during interaction with human cells. The tcf gene cluster was cloned and induced in Escherichia coli and S. Typhi, and the production of intertwined fibres similar to the Cbl (cable) pili of Burkholderia cepacia was observed on the bacterial surface by electron microscopy. In S. Typhi, tcf was expressed more after growth in M63 minimal medium than in standard Luria-Bertani medium. Analysis of the promoter region identified putative binding sites for the global regulators RcsB, ArgR and Fur. The expression of tcf was measured in isogenic strains lacking these global regulators. Under the conditions tested, the results showed that tcf expression was higher in the fur mutant and was regulated by iron concentration. Fur may regulate these fimbriae indirectly via the small RNAs RyhB1 and RyhB2. An isogenic mutant harbouring a deletion of the tcf cluster did not demonstrate any defect in adhesion or invasion of human epithelial cells, or in phagocytosis or survival in macrophages, when compared to the WT serovar Typhi strain. However, the tcf cluster contributed to adherence to human epithelial cells when introduced into E. coli. Thus, tcf genes encode functional fimbriae that can act as an adhesin and may contribute to colonization during typhoid fever.
authors.affiliation: Department of Microbiology, Infectiology and Immunology, Université de Montréal,CP 6128 Succursale Centre-Ville, Montreal, Quebec H3C 3J7,Canada.
authors.forename: Jean-Mathieu
authors.initials: JM
authors.lastname: Leclerc
authors.affiliation: Department of Microbiology, Infectiology and Immunology, Université de Montréal,CP 6128 Succursale Centre-Ville, Montreal, Quebec H3C 3J7,Canada.
authors.forename: Eve-Lyne
authors.initials: EL
authors.lastname: Quevillon
authors.affiliation: Department of Microbiology, Infectiology and Immunology, Université de Montréal,CP 6128 Succursale Centre-Ville, Montreal, Quebec H3C 3J7,Canada.
authors.forename: Yoan
authors.initials: Y
authors.lastname: Houde
authors.affiliation: Department of Microbiology, Infectiology and Immunology, Université de Montréal,CP 6128 Succursale Centre-Ville, Montreal, Quebec H3C 3J7,Canada.
authors.forename: Kiran
authors.initials: K
authors.lastname: Paranjape
authors.affiliation: INRS-Institut Armand-Frappier,531 boulevard des Prairies, Laval, Québec H7V 1B7,Canada.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Dozois
authors.affiliation: Department of Microbiology, Infectiology and Immunology, Université de Montréal,CP 6128 Succursale Centre-Ville, Montreal, Quebec H3C 3J7,Canada.
authors.forename: France
authors.initials: F
authors.lastname: Daigle
mesh_terms: D001422:Bacterial Adhesion / Q000235:genetics* / Q000502:physiology; D001426:Bacterial Proteins / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism; D004847:Epithelial Cells / Q000382:microbiology*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008264:Macrophages / Q000276:immunology / Q000382:microbiology*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012097:Repressor Proteins / Q000378:metabolism; D012485:Salmonella typhi / Q000235:genetics* / Q000472:pathogenicity*; D037521:Virulence Factors / Q000096:biosynthesis / Q000235:genetics*
chemical_list: C087018:ArgR protein, Bacteria; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D037521:Virulence Factors; C068477:ferric uptake regulating proteins, bacterial; C074889:RcsB protein, Bacteria