Mutagenesis of Escherichia coli: a method for determining mutagenic specificity by analysis of tRNA suppressors

• Published in: Mutagenesis Vol. 7; no. 1; p. 41
• Main Authors: Sledziewska-Gójska, E, Grzesiuk, E, Plachta, A, Janion, C
• Format: Journal Article
• Language: English
• Published: England 01.01.1992
• Subjects: Arginine - analysis; Escherichia coli - drug effects; Escherichia coli - genetics; Histidine - analysis; Mutagenesis, Site-Directed - genetics; Mutagens - toxicity; RNA, Bacterial - physiology; RNA, Transfer - physiology; Suppression, Genetic - genetics
• ISSN: 0267-8357
• DOI: 10.1093/mutage/7.1.41

A method for estimating mutagenic specificity in Escherichia coli (argE3, hisG4, thr-1, supE44), based upon the isolation of Arg+ or His+ revertants and identification of tRNA suppressors, is described. The method gives an insight not only into mutagenic pathways but also into the functioning of tRNA. With N-methyl-N'-nitro-N-nitrosoguanidine, 98% of mutations are GC---AT transitions. With N4-hydroxycytidine, 100% are AT---GC transitions. With hydroxylamine, apart from GC---AT transitions, approximately 30% of Arg+ revertants are formed by GC (or AT)---TA transversions. When the chemistry of the mutagenic attack is known, the method allows us to discriminate whether mutations occur on the transcribed or non-transcribed strands of DNA. It has been found that reversion of argE3 to Arg+ is a better monitor of mutagenic pathways than reversion of hisG4 to His+.