Hauser J, Levine A S, Dixon K
EMBO J. 1987 Jan;6(1):63-7. doi: 10.1002/j.1460-2075.1987.tb04719.x.
We have used a simian virus 40 (SV40)-based shuttle vector, pZ189, to analyze the sequence specificity of spontaneous point mutations that arise after transfection of this vector into monkey cells. The majority of the mutants which we studied had multiple base substitutions (mostly G-C----A-T transitions and G-C----T-A transversions) within the 160-bp region sequenced. Almost all of the mutations occurred in the right-hand G-C bp of one of the two following sequences, 5'-TC-3':3'-AG-5' or 5'-CC-3':3'-GG-5'. We postulate that these mutations result from DNA replication infidelity occurring during repair of the transfected DNA which has been damaged by cellular nucleases. The sequence specificity of the mutations suggests an effect of the following nucleotide on misincorporation wherein A (or less frequently T) is preferentially misincorporated opposite C when the next nucleotide inserted is A (or less frequently G). Our results support the utility of the shuttle vector as a model in studies on gene transfer and document the extreme plasticity of DNA transfected into mammalian cells.
我们使用了一种基于猿猴病毒40（SV40）的穿梭载体pZ189，来分析将该载体转染到猴细胞后自发点突变的序列特异性。我们研究的大多数突变体在测序的160 bp区域内有多个碱基替换（主要是G-C→A-T转换和G-C→T-A颠换）。几乎所有的突变都发生在以下两个序列之一的右手边G-C碱基对中，即5'-TC-3':3'-AG-5'或5'-CC-3':3'-GG-5'。我们推测这些突变是由于在修复被细胞核酸酶损伤的转染DNA过程中发生的DNA复制错误所致。突变的序列特异性表明下一个核苷酸对错配掺入有影响，即在插入的下一个核苷酸为A（或较少见的G）时，A（或较少见的T）优先与C错配掺入。我们的结果支持了穿梭载体作为基因转移研究模型的实用性，并证明了转染到哺乳动物细胞中的DNA具有极高的可塑性。
