title: Nucleotide sequence and characterization of the Rhodobacter capsulatus hvrB gene: HvrB is an activator of S-adenosyl-L-homocysteine hydrolase expression and is a member of the LysR family.
abstract: Here we present the nucleotide sequence and characterization of two genes, hvrB and orf5, that are located in the regulatory gene cluster from Rhodobacter capsulatus. The hvrB gene, which encodes a protein with a predicted molecular mass of 32 kDa, is shown to be highly homologous to genes encoding members of the LysR family of bacterial transcriptional regulators. A chromosomal disruption of hvrB is shown to result in the failure to regulate expression from the nearby ahcY and orf5 genes in response to alterations in light intensity. We show by primer extension mapping that the 5' end of ahcY-specific mRNA defines a promoter region exhibiting sequence similarity to known R. capsulatus promoter elements. Our mutational analysis further demonstrates that hvrB autoregulates its own expression in vivo.
authors.affiliation: Department of Biology, Indiana University, Bloomington 47405.
authors.forename: J J
authors.initials: JJ
authors.lastname: Buggy
authors.forename: M W
authors.initials: MW
authors.lastname: Sganga
authors.forename: C E
authors.initials: CE
authors.lastname: Bauer
mesh_terms: D043383:Adenosylhomocysteinase; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D017124:Conserved Sequence; D004789:Enzyme Activation; D015964:Gene Expression Regulation, Bacterial / Q000528:radiation effects; D005798:Genes, Bacterial / Q000235:genetics*; D005809:Genes, Regulator / Q000235:genetics*; D006867:Hydrolases / Q000096:biosynthesis* / Q000235:genetics; D008027:Light; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D016354:Rhodobacter capsulatus / Q000201:enzymology / Q000235:genetics* / Q000528:radiation effects; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C085239:HvrB protein, Rhodobacter capsulatus; D014157:Transcription Factors; C073470:LysR protein, Bacteria; D006867:Hydrolases; D043383:Adenosylhomocysteinase