Ayaki H, Higo K, Yamamoto O
Nucleic Acids Res. 1986 Jun 25;14(12):5013-8. doi: 10.1093/nar/14.12.5013.
M13 mp10 single-stranded phage DNA was irradiated with 60 Co gamma-rays, and transfected into Escherichia coli. One hundred and sixteen mutant clones having lesions in the lac insert were selected, and mutational sites were examined by DNA sequence analysis. Fourteen out of the 15 nucleotide changes thus detected were base substitutions, and the rest was a base addition. Transitions and transversions were almost equal in number. Mutational events were observed at cytosine residues more frequently than at other residues, and the predominant base change was a C ---- T transition. Possible roles in gamma-ray-induced mutagenesis played by the misincorporation of dAMP owing to radiolytic derivatives of cytosine residues and/or formation of apurinic/apyrimidinic sites are discussed.
用60Coγ射线照射M13 mp10单链噬菌体DNA，然后将其转染到大肠杆菌中。挑选出116个在lac插入片段中有损伤的突变克隆，并通过DNA序列分析检查突变位点。如此检测到的15个核苷酸变化中，有14个是碱基替换，其余的是碱基添加。转换和颠换的数量几乎相等。在胞嘧啶残基处观察到的突变事件比在其他残基处更频繁，主要的碱基变化是C→T转换。本文讨论了由于胞嘧啶残基的辐射分解衍生物导致的dAMP错误掺入和/或无嘌呤/无嘧啶位点的形成在γ射线诱导的诱变中可能发挥的作用。
