title: The promoter of the recA gene of Escherichia coli.
abstract: The growth defect of a lambda phage carrying a recA-lacZ fusion was used to select mutations that reduced recA expression. Nine single base changes in the recA promoter were isolated that reduced both induced and basal (repressed) levels of expression. Deletion analysis of the promoter region and mapping of transcripts indicated that there is one main promoter responsible for both basal and induced expression. Some of the mutants displayed a lowered induction ratio, raising the possibility that there is a second, weak promoter that is not regulated by the SOS response. When one of the mutants was examined, it showed normal affinity for LexA repressor binding to the operator site. Binding of RNA polymerase to this mutant promoter, however, was much reduced. Further binding experiments suggested that LexA does not block RNA polymerase binding to the recA promoter, but inhibits a later step in initiation.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston 77225.
authors.forename: J M
authors.initials: JM
authors.lastname: Weisemann
authors.forename: G M
authors.initials: GM
authors.lastname: Weinstock
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D016384:Consensus Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011401:Promoter Regions, Genetic; D011938:Rec A Recombinases / Q000235:genetics* / Q000378:metabolism; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases; D011938:Rec A Recombinases; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein