title: Regulation of the expression of the Vibrio parahaemolyticus peuA gene encoding an alternative ferric enterobactin receptor.
abstract: A pvsB-vctA-irgA triple deletion mutant of Vibrio parahaemolyticus can utilize enterobactin under iron-limiting conditions by inducing a previously undescribed receptor, PeuA (VPA0150), in response to extracellular alkaline pH and enterobactin. In silico analyses revealed the existence of a two-component regulatory system operon, peuRS, immediately upstream of peuA, which constitutes an operon with the TonB2 system genes. Both the peuRS and peuA-tonB2 operons were found to be upregulated under iron-limiting conditions in a ferric uptake regulator (Fur)-dependent manner. The involvement of peuA and peuRS in enterobactin utilization was analyzed by complementation experiments using deletion mutants. Primer extension analysis indicated that, under iron-limiting conditions, the transcription of peuA was initiated from the +1 site at pH 7.0 and from both the +1 and +39 sites at pH 8.0 in the presence of enterobactin. The +39 transcript was absent from the peuRS deletion mutant. Secondary structure prediction of their 5'-untranslated regions suggested that translation initiation is blocked in the +1 transcript, but not in the +39 transcript. Consistent with this, in vitro translation analysis demonstrated that production of PeuA was determined only by the +39 transcript. These studies establish a novel gene regulation mechanism in which the two-component regulatory system PeuRS enhances expression of the alternative +39 transcript that possesses non-inhibitory structure, allowing the peuA expression to be regulated at the translation stage.
authors.affiliation: Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Tanabe
authors.affiliation: Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Kato
authors.affiliation: Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Shiuchi
authors.affiliation: Department of Microbiology, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka, Japan.
authors.forename: Katsushiro
authors.initials: K
authors.lastname: Miyamoto
authors.affiliation: Department of Microbiology, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsujibo
authors.affiliation: Laboratory of Infectious Diseases, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Maki
authors.affiliation: Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Funahashi
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D009876:Operon / Q000502:physiology; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000235:genetics; D014158:Transcription, Genetic / Q000502:physiology*; D014736:Vibrio parahaemolyticus / Q000235:genetics / Q000378:metabolism*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D011956:Receptors, Cell Surface; C029489:enterobactin receptor