title: Translational repression in the arginine system of Escherichia coli.
abstract: Translation of bacterial mRNA, divorced from transcription, has been obtained for enzymes of arginine synthesis; evidence has been acquired for repression by arginine at the level of translation. mRNAs for acetylornithinase and ornithine transcarbamylase were accumulated by arginine starvation of argR(+) and argR(-) arginine auxotrophs derived from Escherichia coli K12. Further transcription was inhibited with rifampicin or miracil D, and enzyme formation was measured in the presence of either an excess of, or a restricted supply of, arginine. For the argR(+) strain 961, little mRNA was found without starvation; for the argR(-) strain 977, a considerable amount of mRNA was demonstrated even without starvation. There was relatively little translation for the argR(+) strain, but not for the argR(-) strain, in the presence of excess arginine, apparently due to an accelerated degradation of mRNA in the argR(+) strain under repressive conditions.
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism; D001120:Arginine / Q000096:biosynthesis*; D004926:Escherichia coli / Q000378:metabolism*; D005809:Genes, Regulator; D005815:Genetic Code; D005827:Genetics, Microbial; D009154:Mutation; D009954:Ornithine Carbamoyltransferase / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis*; D012293:Rifampin / Q000494:pharmacology
chemical_list: D012333:RNA, Messenger; D001120:Arginine; D009954:Ornithine Carbamoyltransferase; D000581:Amidohydrolases; D012293:Rifampin