title: Regulation of phenylalanine biosynthesis in Escherichia coli K-12: control of transcription of the pheA operon.
abstract: Bacteriophage lambda ppheA-lac was used to obtain strains of Escherichia coli K-12 in which pheA and lacZ are each transcribed from a separate pheA promoter. Mutants in which both beta-galactosidase and chorismate mutase P-prephenate dehydratase (the pheA gene product) were derepressed were isolated, and a transacting gene (pheR) was identified. pheR was mapped at min 93 on the E. coli chromosome; pheR mutants acquired the wild-type phenotype when either F117 (which covers the 93-min region) or F116 (which covers min 59 to 65) was introduced into the cell. A rifampin resistance mutation, rpoB366, was found to derepress transcription of the pheA operon. pheR and rpoB366 affected two different systems for the phenylalanine-mediated control of pheA. A mutation in miaA (trpX), a gene known to be involved in attenuation in the tryptophan operon, was also shown to increase transcription of the pheA gene.
mesh_terms: D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D004274:DNA, Recombinant; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D005809:Genes, Regulator; D006836:Hydro-Lyases / Q000235:genetics*; D009876:Operon; D010649:Phenylalanine / Q000096:biosynthesis*; D011302:Prephenate Dehydratase / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D004274:DNA, Recombinant; D010649:Phenylalanine; D006836:Hydro-Lyases; D011302:Prephenate Dehydratase