title: ArcA works with Fnr as a positive regulator of Vitreoscilla (bacterial) hemoglobin gene expression in Escherichia coli.
abstract: Low oxygen induction of the bacterial (Vitreoscilla) hemoglobin gene (vgb) by the Arc system was investigated, as the presumptive vgb Crp site was found to have 73% identity to the Escherichia coli consensus ArcA site. The role of ArcA by itself and with Fnr was examined in E. coli using the wild type vgb promoter and promoter mutants affecting the Fnr and Crp (presumptive ArcA) sites and E. coli strains with all combinations of fnr+/fnr-, arcA+/arcA- genotypes. High-level transcription required both ArcA and Fnr systems to be functional; low oxygen induction required at least one of ArcA and Fnr to be intact. Levels of Vitreoscilla hemoglobin protein (VHb) followed the same trends as seen with mRNA, although the relative decreases in the mutants relative to wild type were less than with transcription. Growth of cells was stimulated by VHb, generally to a greater extent as VHb levels increased.
authors.affiliation: Biology Division, Department of Biological, Chemical, and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Yang
authors.forename: Dale A
authors.initials: DA
authors.lastname: Webster
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Stark
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D006454:Hemoglobins / Q000096:biosynthesis / Q000235:genetics*; D007506:Iron-Sulfur Proteins / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010100:Oxygen; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D054793:Truncated Hemoglobins; D020589:Vitreoscilla / Q000235:genetics*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C060704:FNR protein, E coli; D006454:Hemoglobins; D007506:Iron-Sulfur Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012097:Repressor Proteins; D054793:Truncated Hemoglobins; C041610:arcA protein, E coli; C082613:hemoglobin protein, Vitreoscilla; D010100:Oxygen