A determination of mutagen specificity in bacteria using nonsense mutants of bacteriophage T4.

摘要: Abstract We present a method for the determination of mutagen specificity in bacteria, using an Escherichia coli strain that is mutant because amber triplet gene necessary arginine biosynthesis. A large number revertants occurring spontaneously and after treatment with 2-aminopurine, [5-3H]uracil radioactive decay, ethyl methanesulfonate, 5-bromodeoxyuridine, hydroxylamine ultraviolet light were tested their ability to support growth 24 mutants one ochre bacteriophage T4. Regardless used produce revertants, only 6 patterns, called classes, phage obtained. Revertants classes 1, 2 3 contained suppressors, 4 5 suppressors those class 6, since they suppressed none phages used, assumed be structural revertants. By comparing patterns obtained bacterial strains characterized amino acid inserted by revertant or was inferred. Strikingly different distributions into observed some mutagens. 2-Aminopurine, decay found very specific action. Assuming reversion occurred single base changes DNA specifying either codon certain sRNA anticodons, it also possible infer produced The anticodons altered are can become inverse complements UAG UAA changes.