Genetic analysis of a streptomycin-resistant Escherichia coli mutant temperature-sensitive for nonsense suppression.
Continuing the genetic and biochemical characterization of the streptomycin-resistant Escherichia coli mutant LD1, we confirmed that LD1 is temperature-sensitive for suppression of nonsense codons, and that this phenotype of the mutant and its streptomycin-resistance are genetically linked and are probably caused by a single mutation, strA(LD1). We also isolated a spontaneous revertant, called LD1-R, which partially relieves the restriction of nonsense suppression caused by the strA(LD1) mutation. LD1-R is derived by an additional mutation (revA) which is closely linked to strA(LD1). We further demonstrate that the weak suppression of a lacZUGA mutation in a suppressor-free strain, which probably takes place by normal tRNA1rp, can be detected by the use of the chromagenic substance x-gal (5-Bromo-4-chloro-3-indolyl-beta-D-Galactopyranoside).
D003062:Codon; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D008040:Genetic Linkage; D009154:Mutation; D013307:Streptomycin / Q000494:pharmacology*; D013489:Suppression, Genetic; D013696:Temperature
D003062:Codon; D013307:Streptomycin