Ripley L S
Proc Natl Acad Sci U S A. 1982 Jul;79(13):4128-32. doi: 10.1073/pnas.79.13.4128.
A model is described for the templated production of frameshift and base-substitution mutations mediated through aberrant DNA structures arising as a consequence of quasi-palindromic DNA sequences. Two general mechanisms are considered. One evokes the formation and processing of imperfect DNA secondary structures (hairpins) for the production of mutations. The other evokes a "strand switch" during DNA synthesis which, in a manner unique to quasi-palindromic sequences, may be resolved to produce frameshift or base-substitution mutations, or both. It is the unique combination of symmetrical and asymmetrical elements of the quasi-palindromic sequence itself that provides the basis for both models. Through the mechanisms described, the symmetrical elements permit unusually paired DNA substrates, and the asymmetrical elements permit templated insertions, deletions, and base substitutions. The model predicts a class of mutations--simultaneously frameshifts and base substitutions--whose sequences can be predicted from a local quasi-palindromic sequence. This prediction appears to be met by a significant fraction (more than 15%) of frameshift mutations in the iso-1-cytochrome c gene of Saccharomyces cerevisiae.
本文描述了一种模型，用于通过准回文DNA序列产生的异常DNA结构介导的移码突变和碱基替换突变的模板化产生。考虑了两种一般机制。一种机制引发不完美DNA二级结构（发夹）的形成和加工以产生突变。另一种机制引发DNA合成过程中的“链切换”，以准回文序列特有的方式，可解析产生移码突变或碱基替换突变，或两者皆有。正是准回文序列本身的对称和不对称元件的独特组合为这两种模型提供了基础。通过所描述的机制，对称元件允许异常配对的DNA底物，不对称元件允许模板化的插入、缺失和碱基替换。该模型预测了一类突变——同时发生移码突变和碱基替换——其序列可从局部准回文序列预测。酿酒酵母异-1-细胞色素c基因中相当一部分（超过15%）的移码突变似乎符合这一预测。
