title: Mutations resulting in promoter-like sequences which enhance the expression of araC in Salmonella typhimurium.
abstract: The araC gene in Salmonella typhimurium is autogeneously regulated. Nine non-self-regulated mutants were isolated by selecting for increased expression of an araC-lacZ fusion in the presence of a repressing AraC protein. S1 mapping experiments demonstrated that the effect of the mutations was to increase the amount of araC mRNA in the cell. The 5'-end of the major araC transcript was the same in the wild-type (wt) and mutant strains. DNA sequence analysis showed that all nine mutations occurred in the araC promoter. Two mutations were a G-to-T transversion at position -25, six were a G-to-T transversion at position -47 and one was a single bp deletion at position -83. The data suggest that the mutations have created a new RNA polymerase binding site which enhances transcription from the wt start point.
mesh_terms: D001089:Arabinose / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004262:DNA Restriction Enzymes; D005796:Genes; D005798:Genes, Bacterial; D009154:Mutation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012486:Salmonella typhimurium / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D001089:Arabinose; D004262:DNA Restriction Enzymes