title: Genetic organization of the yersiniabactin biosynthetic region and construction of avirulent mutants in Yersinia pestis.
abstract: We have identified an approximately 22-kb region of the pgm locus of Yersinia pestis KIM6+ which encodes a number of iron-regulated proteins involved in the biosynthesis of the Y. pestis cognate siderophore, yersiniabactin (Ybt), and which is located immediately upstream of the pesticin/yersiniabactin receptor gene (psn). Sequence analysis and the construction of insertion and deletion mutants allowed us to determine the putative location of the irp1 gene and the positions of irp2, ybtT, and ybtE within the ybt operon. Mutations in the irp1, irp2, or ybtE gene yielded strains defective in siderophore production. Mutant strains were unable to grow on iron-deficient media at 37 degrees C but could be cross-fed by culture supernatants from yersiniabactin-producing strains of Y. pestis grown under iron-limiting conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of whole-cell extracts from Ybt+ and Ybt- strains grown in iron-deficient media revealed that expression of ybt-encoded proteins is not only iron regulated but also influenced by the presence of the siderophore itself. Finally, Y. pestis strains with mutations in either the psn or irp2 gene were avirulent in mice when inoculated subcutaneously.
authors.affiliation: Department of Microbiology and Immunology, University of Kentucky, Lexington 40536-0084, USA.
authors.forename: S W
authors.initials: SW
authors.lastname: Bearden
authors.forename: J D
authors.initials: JD
authors.lastname: Fetherston
authors.forename: R D
authors.initials: RD
authors.lastname: Perry
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000032:analysis; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004758:Enterobactin / Q000378:metabolism*; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D007501:Iron / Q000378:metabolism; D033862:Iron-Binding Proteins; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009876:Operon; D033902:Periplasmic Binding Proteins; D045331:Photosystem I Protein Complex; D010957:Plasmids; D011506:Proteins / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics; D011995:Recombination, Genetic; D016415:Sequence Alignment; D017384:Sequence Deletion; D014774:Virulence; D015010:Yersinia pestis / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C090748:FyuA protein, Yersinia; D033862:Iron-Binding Proteins; D008565:Membrane Proteins; D033902:Periplasmic Binding Proteins; D045331:Photosystem I Protein Complex; D011506:Proteins; D011956:Receptors, Cell Surface; C089909:photosystem I, psaB subunit; D004758:Enterobactin; D007501:Iron