title: Transcriptional regulation of Alcaligenes eutrophus hydrogenase genes.
abstract: Alcaligenes eutrophus H16 produces a soluble hydrogenase (SH) and a membrane-bound hydrogenase (MBH) which catalyze the oxidation of H2, supplying the organism with energy for autotrophic growth. The promoters of the structural genes for the SH and the MBH, PSH and PMBH, respectively, were identified by means of the primer extension technique. Both promoters were active in vivo under hydrogenase-derepressing conditions but directed only low levels of transcription under condition which repressed hydrogenase synthesis. The cellular pools of SH and MBH transcripts under the different growth conditions correlated with the activities of the respective promoters. Also, an immediate and drastic increase in transcript pool levels occurred upon derepression of the hydrogenase system. Both promoters were dependent on the minor sigma factor sigma 54 and on the hydrogenase regulator HoxA in vivo. PSH was stronger than PMBH under both heterotrophic and autotrophic growth conditions. The two promoters were induced at approximately the same rates upon derepression of the hydrogenase system in diauxic cultures. The response regulator HoxA mediated low-level activation of PSH and PMBH in a heterologous system.
authors.affiliation: Institut für Biologie, Humboldt-Universität zu Berlin, Germany. edward=schwartz@biologie.hu-berlin.de
authors.forename: E
authors.initials: E
authors.lastname: Schwartz
authors.forename: U
authors.initials: U
authors.lastname: Gerischer
authors.forename: B
authors.initials: B
authors.lastname: Friedrich
mesh_terms: D000421:Alcaligenes / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005798:Genes, Bacterial; D018398:Homeodomain Proteins; D006864:Hydrogenase / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D051877:RNA Polymerase Sigma 54; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012808:Sigma Factor / Q000378:metabolism; D012995:Solubility; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D018398:Homeodomain Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012808:Sigma Factor; D015534:Trans-Activators; C497751:rpoN protein, E coli; C088144:HoxA protein; D006864:Hydrogenase; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54