title: GcvA binding site 1 in the gcvTHP promoter of Escherichia coli is required for GcvA-mediated repression but not for GcvA-mediated activation.
abstract: GcvA binds to three sites in the gcvTHP control region, from base -34 to -69 (site 1), from base -214 to -241 (site 2) and from base -242 to -271 (site 3). Previous results suggested that sites 3 and 2 are required for both GcvA-dependent activation and repression of a gcvT::lacZ fusion. However, the results were less clear as to the role of site 1. To determine the role of site 1 in regulation, single and multiple base changes were made in site 1 and tested for their ability to alter GcvA-mediated activation and GcvA/GcvR-mediated repression. Several of the mutants were also tested for effects on GcvA binding to site 1 and the ability of GcvA to bend DNA at site 1. The results are consistent with site 1 playing primarily a role in negative regulation of the gcvTHP operon.
authors.affiliation: Department of Microbiology, The University of Iowa, Iowa City, IA 52242, USA1.
authors.forename: Laura D
authors.initials: LD
authors.lastname: Wonderling
authors.affiliation: Department of Microbiology, The University of Iowa, Iowa City, IA 52242, USA1.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Urbanowski
authors.affiliation: Department of Microbiology, The University of Iowa, Iowa City, IA 52242, USA1.
authors.forename: George V
authors.initials: GV
authors.lastname: Stauffer
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D009690:Nucleic Acid Conformation; D009876:Operon; D010641:Phenotype; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C095454:GcvA protein, E coli; D014157:Transcription Factors