title: A new conditional lethal mutator (dnaQ49) in Escherichia coli K12.
abstract: A conditional lethal mutator, dnaQ49, was found in Escherichia coli K12. The dnaQ49 mutation caused stimulation of rifampicin-, nalidixic acid- and streptomycin-resistant mutation frequencies 100 to 2000 fold at 30 degrees C and the frequencies were further increased 50 to 100 fold at 35 degrees C or higher temperatures. Cells carrying dnaQ49 were unable to grow in salt-free L-broth at 44.5 degrees C, and DNA synthesis but not protein synthesis of the cells was suppressed under the restrictive conditions. The dnaQ gene was located at about 5 min on the E. coli linkage map and the order of the genes residing in this region was determined to be ton A-dnaE-metD-dnaQ-pro A.
mesh_terms: D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D004269:DNA, Bacterial / Q000096:biosynthesis*; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000235:genetics*; D005804:Genes, Lethal; D006358:Hot Temperature; D009154:Mutation; D009268:Nalidixic Acid / Q000494:pharmacology; D012293:Rifampin / Q000494:pharmacology; D013307:Streptomycin / Q000494:pharmacology
chemical_list: D004269:DNA, Bacterial; D009268:Nalidixic Acid; D012293:Rifampin; D013307:Streptomycin