title: Roles of RpoS (sigmaS), IHF and ppGpp in the expression of the hmp gene encoding the flavohemoglobin (Hmp) of Escherichia coli K-12.
abstract: The Escherichia coli K-12 gene hmp encodes the flavohemoglobin Hmp. A hmp promoter phi(hmp-lacZ)-operon fusion was constructed in the chromosome and its activity measured during the growth cycle. Logarithmically growing cultures had low levels of phi(hmp-lacZ) expression, which increased two-fold at the onset of stationary phase in rich medium. The effect was abolished in a strain carrying a null allele of the gene rpoS encoding the stationary phase-specific sigma subunit of RNA polymerase sigmaS. A himA mutation resulted in a 1.5-fold increase in expression of phi(hmp-lacZ) but did not affect growth phase-dependent regulation. A single transcriptionial start site was found for hmp, located 38 bp upstream of the initiation codon. Putative Fnr boxes at positions -2 to +11 occur in the hmp promoter region.
authors.affiliation: The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, UK.
authors.forename: J
authors.initials: J
authors.lastname: Membrillo-Hernandez
authors.forename: G M
authors.initials: GM
authors.lastname: Cook
authors.forename: R K
authors.initials: RK
authors.lastname: Poole
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology*; D001483:Base Sequence; D002352:Carrier Proteins; D002373:Cyclic AMP Receptor Protein / Q000502:physiology; D004093:Dihydropteridine Reductase; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D006159:Guanosine Tetraphosphate / Q000502:physiology*; D006420:Hemeproteins / Q000235:genetics*; D034982:Integration Host Factors; D008969:Molecular Sequence Data; D009154:Mutation; D009247:NADH, NADPH Oxidoreductases; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D002373:Cyclic AMP Receptor Protein; D029968:Escherichia coli Proteins; D006420:Hemeproteins; D034982:Integration Host Factors; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D006159:Guanosine Tetraphosphate; D004093:Dihydropteridine Reductase; C076538:hmp protein, E coli; D009247:NADH, NADPH Oxidoreductases