title: Organization and PprB-dependent control of the Pseudomonas aeruginosa tad Locus, involved in Flp pilus biology.
abstract: Bacterial attachment to the substratum involves several cell surface organelles, including various types of pili. The Pseudomonas aeruginosa Tad machine assembles type IVb pili, which are required for adhesion to abiotic surfaces and to eukaryotic cells. Type IVb pili consist of a major subunit, the Flp pilin, processed by the FppA prepilin peptidase. In this study, we investigated the regulatory mechanism of the tad locus. We showed that the flp gene is expressed late in the stationary growth phase in aerobic conditions. We also showed that the tad locus was composed of five independent transcriptional units. We used transcriptional fusions to show that tad gene expression was positively controlled by the PprB response regulator. We subsequently showed that PprB bound to the promoter regions, directly controlling the expression of these genes. We then evaluated the contribution of two genes, tadF and rcpC, to type IVb pilus assembly. The deletion of these two genes had no effect on Flp production, pilus assembly, or Flp-mediated adhesion to abiotic surfaces in our conditions. However, our results suggest that the putative RcpC protein modifies the Flp pilin, thereby promoting Flp-dependent adhesion to eukaryotic cells.
authors.affiliation: Membrane Complexes and Pathogenicity in Pseudomonas aeruginosa, CNRS LISM (UPR9027)-Aix-Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
authors.forename: Christophe S
authors.initials: CS
authors.lastname: Bernard
authors.forename: Christophe
authors.initials: C
authors.lastname: Bordi
authors.forename: Elise
authors.initials: E
authors.lastname: Termine
authors.forename: Alain
authors.initials: A
authors.lastname: Filloux
authors.forename: Sophie
authors.initials: S
authors.lastname: de Bentzmann
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D004847:Epithelial Cells / Q000382:microbiology; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D006801:Humans; D009876:Operon; D011485:Protein Binding; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000254:growth & development / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; C113731:Flp protein, bacteria; D036781:Fimbriae Proteins