Cabral Neto J B, Cabral R E, Margot A, Le Page F, Sarasin A, Gentil A
Laboratory of Molecular Genetics, UPR 42, Institut de Recherches Scientifiques sur le Cancer, Villejuif, France.
J Mol Biol. 1994 Jul 29;240(5):416-20. doi: 10.1006/jmbi.1994.1457.
The coding properties of abasic sites have been studied in mammalian cells using a single-stranded shuttle vector carrying a unique abasic site. The probe was produced by digestion with the uracil DNA glycosylase of a uracil-containing oligonucleotide which was inserted in the single-stranded vector. After replication in monkey COS7 cells able to support DNA replication of the vector, the plasmid progeny were isolated in bacteria. DNA sequencing of rescued plasmids showed that replication of abasic sites does not lead to preferential insertion of a given base opposite the non-coding site. The four bases were inserted with a frequency which was not statistically different from a random distribution. It appears therefore that the "A rule insertion" opposite a unique abasic site does not apply, at least with the sequence we used, for an exogenous single-stranded DNA replicated in mammalian cells. It was not necessary to induce SOS-like conditions by pretreatment of host cells, in order to replicate abasic sites.
利用携带单个无碱基位点的单链穿梭载体，在哺乳动物细胞中研究了无碱基位点的编码特性。该探针是通过用尿嘧啶DNA糖基化酶消化插入单链载体中的含尿嘧啶寡核苷酸而产生的。在能够支持该载体DNA复制的猴COS7细胞中复制后，在细菌中分离出质粒后代。对拯救质粒的DNA测序表明，无碱基位点的复制不会导致在非编码位点对面优先插入特定碱基。四种碱基的插入频率与随机分布在统计学上没有差异。因此，至少对于我们使用的序列而言，在哺乳动物细胞中复制的外源单链DNA，独特无碱基位点对面的“A规则插入”并不适用。为了复制无碱基位点，无需通过对宿主细胞进行预处理来诱导类似SOS的条件。
