title: Activation of the ompC gene by the OmpR protein in Escherichia coli. The cis-acting upstream sequence can function in both orientations with respect to the canonical promoter.
abstract: Expression of the ompC gene coding for an outer membrane protein of Escherichia coli is regulated by a transcriptional activation mechanism that requires the ompR gene product that acts on nucleotide sequences located upstream of the -35 and -10 regions of the ompC promoter. Using an ompC-lacZ fusion gene, the orientation of the cis-acting upstream sequence (OmpR-binding site) with respect to the canonical -35 and -10 regions (RNA polymerase-binding site) was changed. The ompC gene was activated in an OmpR-dependent manner even when the upstream sequence was in the reverse orientation with respect to the -35 and -10 regions, providing that these two DNA elements were aligned stereospecifically on the DNA helix. Evidence is presented that the upstream sequence can increase the transcription efficiency of the ompC promoter in a manner relatively independent of its orientation with respect to the -35 and -10 regions.
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D005786:Gene Expression Regulation; D005796:Genes; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001616:beta-Galactosidase