title: Identification and characterization of Aeromonas hydrophila genes encoding the outer membrane receptor of ferrioxamine B and an AraC-type transcriptional regulator.
abstract: We found that, under iron-limiting conditions, Aeromonas hydrophila ATCC 7966(T) could utilize the xenosiderophore desferrioxamine B (DFOB) for growth by inducing the expression of its own outer membrane receptor. Two consecutive genes, desR and desA, were selected as candidates involved in DFOB utilization. The presence of the ferric-uptake regulator boxes in their promoters suggested that these genes are under iron-dependent regulation. Mutation of desA, a gene that encodes the outer membrane receptor of ferrioxamine B, disrupted the growth of the amonabactin-deficient mutant in the presence of DFOB. β-Galactosidase reporter assays and reverse transcriptase-quantitative PCR demonstrated that desR, a gene that encodes an AraC-like regulator homolog is required for the induction of desA transcription in the presence of DFOB and under iron-limiting conditions. The functions of desA and desR were analyzed using complementation experiments. Our data provided evidence that DesA is powered primarily by the TonB2 system.
authors.affiliation: a Laboratory of Hygienic Chemistry , College of Pharmaceutical Sciences, Matsuyama University , Matsuyama , Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Funahashi
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Tanabe
authors.forename: Jun
authors.initials: J
authors.lastname: Maki
authors.forename: Katsushiro
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsujibo
authors.forename: Shigeo
authors.initials: S
authors.lastname: Yamamoto
mesh_terms: D016980:Aeromonas hydrophila / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D051777:AraC Transcription Factor / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D003676:Deferoxamine / Q000378:metabolism*; D004734:Energy Metabolism; D005290:Ferric Compounds / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D005810:Multigene Family / Q000235:genetics; D009876:Operon / Q000235:genetics; D010641:Phenotype; D017384:Sequence Deletion; D013379:Substrate Specificity; D014158:Transcription, Genetic
chemical_list: D051777:AraC Transcription Factor; D001425:Bacterial Outer Membrane Proteins; D005290:Ferric Compounds; C002577:ferrioxamine B; D007501:Iron; D003676:Deferoxamine
keywords: Aeromonas hydrophila; AraC-type regulator; TonB; desferrioxamine B; outer membrane receptor