title: Vir90, a virulence-activated gene coding for a Bordetella pertussis iron-regulated outer membrane protein.
abstract: Bordetella pertussis undergoes phenotypic changes modulated by the bvgAS locus, which regulates the expression of many genes related to virulence and immunogenicity. We previously reported the N-terminal sequence of a 90 kDa bvg-regulated outer membrane protein (OMP) of B. pertussis (SWISS-PROT accession No. p81549), a novel potential virulence factor that we named Vir90. The open reading frames (ORFs) which potentially code for Vir90 in B. pertussis, B. parapertussis and B. bronchiseptica were identified by computer analysis of the genomic sequences available for the three Bordetella species. Nucleotide sequence analysis of the vir90 upstream region revealed the presence of a putative promoter, a BvgA binding site and a putative Fur binding site. The B. pertussis Vir90 protein showed significant homology with ferrisiderophore receptors from Gram-negative bacteria. An antiserum raised against Vir90His recombinant protein recognized the 90-kDa protein in immunoblots of OMPs from these three virulent Bordetella species. The accumulation of the Vir90 protein increased 4-fold under low iron growth conditions. Therefore, the vir90 gene is expressed in the tested species and its expression is regulated positively by the BvgAS system and negatively under high iron concentration, likely by Fur.
authors.affiliation: Cátedra de Microbiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina. bpasseri@ffyb.uba.ar
authors.forename: Beatriz N
authors.initials: BN
authors.lastname: Passerini de Rossi
authors.forename: Laura E
authors.initials: LE
authors.lastname: Friedman
authors.forename: Cora B
authors.initials: CB
authors.lastname: Belzoni
authors.forename: Silvana
authors.initials: S
authors.lastname: Savino
authors.forename: Beatrice
authors.initials: B
authors.lastname: Aricò
authors.forename: Rino
authors.initials: R
authors.lastname: Rappuoli
authors.forename: Vega
authors.initials: V
authors.lastname: Masignani
authors.forename: Mirta A
authors.initials: MA
authors.lastname: Franco
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D001886:Bordetella pertussis / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D015964:Gene Expression Regulation, Bacterial; D007501:Iron / Q000494:pharmacology; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000378:metabolism; D017385:Sequence Homology; D014157:Transcription Factors / Q000378:metabolism; D014774:Virulence; D010566:Virulence Factors, Bordetella / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C065601:BvgA protein, Bacteria; D011994:Recombinant Proteins; D014157:Transcription Factors; D010566:Virulence Factors, Bordetella; C080662:bvgS protein, Bordetella pertussis; D007501:Iron