title: Isolation and characterization of amber mutations in gene dnaA of escherichia coli K-12.
abstract: Amber mutants with defects in the dnaA gene of Escherichia coli K-12 were isolated after localized mutagenesis of the tna-dnaA region of the chromosome. We isolated 36 mutants defective in the initiation of deoxyribonucleic acid replication as determined by their dependence upon integrative suppression by a P2 sig5 prophage. Three of the 36 mutants were shown to contain amber mutations through the use of a temperature-sensitive amber suppressor. These mutations, which mapped between gyrB and tna, were characterized genetically and biochemically as amber mutations in dnaA.
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D002874:Chromosome Mapping; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D005796:Genes; D005816:Genetic Complementation Test; D009154:Mutation; D014161:Transduction, Genetic
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial