title: cis-acting ompF mutations that result in OmpR-dependent constitutive expression.
abstract: OmpR and EnvZ differentially control the transcription of the major outer membrane porin genes, ompF and ompC, in Escherichia coli in response to the osmolarity of the medium. We have previously provided evidence that OmpR works both positively and negatively at the ompF promoter to give the characteristic switch from OmpF to OmpC production with increasing osmolarity. Here, we describe the isolation of cis-acting ompF mutations that affect negative regulation by OmpR by affecting the three-dimensional structure of the promoter region as measured by agarose gel mobility. These results further clarify the mechanism by which OmpR negatively regulates ompF expression, suggesting a model in which OmpR forms a repressive loop in the ompF promoter region.
authors.affiliation: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544-1014.
authors.forename: J M
authors.initials: JM
authors.lastname: Slauch
authors.forename: T J
authors.initials: TJ
authors.lastname: Silhavy
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010641:Phenotype; D018272:Porins; D011401:Promoter Regions, Genetic; D011995:Recombination, Genetic; D014158:Transcription, Genetic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D018272:Porins