Gentil A, Renault G, Madzak C, Margot A, Cabral-Neto J B, Vasseur J J, Rayner B, Imbach J L, Sarasin A
Laboratory of Molecular Genetics, Institut de Recherches Scientifiques sur le Cancer, Villejuif, France.
Biochem Biophys Res Commun. 1990 Dec 14;173(2):704-10. doi: 10.1016/s0006-291x(05)80092-0.
The mutagenic properties of a true unique abasic site located opposite a guanine residue were studied. An oligonucleotide containing a chemically-produced abasic site was inserted into a shuttle vector able to replicate both in simian cells and in bacteria. Plasmid DNA was rescued from simian cells and screened in bacteria by differential hybridization with a labelled oligonucleotide probe. Mutations were easily detected and sequenced. Results showed that opposite a guanine the abasic site was error free repaired or replicated by mammalian cells with an efficiency of 99%. Point mutations occurred at a frequency of approximately 1% in control host cells and at more than 3% in UV-pre-irradiated host cells. Adenine, cytosine or thymine were found to have been inserted opposite the abasic site. No preferential insertion for a particular base was observed in contrast to that reported in bacteria.
研究了位于鸟嘌呤残基对面的真正独特的无碱基位点的诱变特性。将含有化学合成无碱基位点的寡核苷酸插入到能够在猴细胞和细菌中复制的穿梭载体中。从猴细胞中拯救出质粒DNA，并通过与标记的寡核苷酸探针进行差异杂交在细菌中进行筛选。突变很容易被检测和测序。结果表明，在哺乳动物细胞中，与鸟嘌呤相对的无碱基位点以99%的效率被无差错修复或复制。点突变在对照宿主细胞中的发生率约为1%，在紫外线预照射的宿主细胞中的发生率超过3%。发现在无碱基位点对面插入了腺嘌呤、胞嘧啶或胸腺嘧啶。与细菌中报道的情况相反，未观察到对特定碱基的优先插入。
