title: Regulation of the ompC gene of Escherichia coli. Involvement of three tandem promoters.
abstract: ompC expression in Escherichia coli K-12 is known to be regulated by the ompB locus, comprising the ompR and envZ genes, and the OmpR protein is believed to act as a positive transcriptional factor. We examined the transcriptional capability of the ompC gene in vitro and found that RNA polymerase could transcribe ompC without a requirement for other transcriptional factors. Furthermore, transcripts from three tandem promoters in ompC were identified in vitro. We employed oligonucleotide-directed site-specific mutagenesis to dissect the promoter region of the gene and assayed the promoters separately for transcriptional ability using fusions to the lacZ gene. The levels of beta-galactosidase indicate that ompC expression in vivo is dependent on the function of at least one of the upstream promoters. The function of OmpR appears to be the enhancement of a basal level of ompC expression. From the results of our experiments, the site of action of OmpR was deduced to be in the vicinity of the upstream promoters of ompC.
mesh_terms: D001483:Base Sequence; D004262:DNA Restriction Enzymes; D004926:Escherichia coli / Q000235:genetics*; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D009154:Mutation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
chemical_list: D004262:DNA Restriction Enzymes