THYMIDINE-INDUCED MUTATIONS IN MAMMALIAN-CELLS - SEQUENCE SPECIFICITY AND IMPLICATIONS FOR MUTAGENESIS INVIVO
THYMIDINE-INDUCED MUTATIONS IN MAMMALIAN-CELLS - SEQUENCE SPECIFICITY AND IMPLICATIONS FOR MUTAGENESIS INVIVO
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DOI：
10.1073/pnas.89.7.2829
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发表时间：
1992-04-01
影响因子：
11.1
通讯作者：
DAVIDSON, RL
中科院分区：
文献类型：
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作者：
KRESNAK, MT;DAVIDSON, RL
哺乳动物细胞内核苷酸前体库的不平衡可导致DNA复制过程中诱导突变。 通过使用穿梭载体系统在我们的实验室开发的，我们已经分析了在小鼠A9细胞中诱导的突变的序列特异性的细胞暴露于高浓度的胸苷。 在这些研究中，诱变的目标是稳定整合到小鼠细胞染色体DNA中的细菌gpt基因。 本实验室以前的研究已经产生了一个大的面板的黄嘌呤鸟嘌呤磷酸核糖转移酶（EC 2.4.2.22）阴性突变株，具有单碱基突变的gpt编码序列。 本研究利用四个黄嘌呤鸟嘌呤磷酸核糖转移酶阴性突变株系，以评估胸苷在四种序列背景下鸟嘌呤残基处诱导的突变频率：GG双联体的5'和3'鸟嘌呤残基、GGG三联体的中间鸟嘌呤残基和GGGG四联体的3'鸟嘌呤残基。 本研究的结果表明，用高浓度胸苷处理培养的细胞可导致G. C-> A.T转换突变，其优先发生在两个或更多个相邻鸟嘌呤序列的3'鸟嘌呤残基处。 在其3'侧由其它鸟嘌呤残基侧接的鸟嘌呤残基比在其3'侧由不同碱基侧接的鸟嘌呤残基少几倍地被胸苷突变。 这项研究表明，胸苷诱导突变的序列特异性模式，并建议在体内诱变的影响。
Imbalances in the intracellular nucleotide precursor pools in mammalian cells can result in the induction of mutations during the DNA replication process. By using a shuttle vector system developed in our laboratory, we have analyzed the sequence specificity of mutations induced in mouse A9 cells by exposure of the cells to a high concentration of thymidine. The target for mutagenesis in these studies was the bacterial gpt gene stably integrated into the chromosomal DNA of the mouse cells. Previous studies in this laboratory had generated a large panel of xanthine guanine phosphoribosyl-transferase (EC 2.4.2.22)-negative mutant lines that possess single-base mutations within the gpt coding sequence. This study utilized four xanthine guanine phosphoribosyltransferase-negative mutant lines to assess the frequency of mutation induced by thymidine at guanine residues in four sequence contexts: the 5' and 3' guanine residues of a GG doublet, the middle guanine residue of a GGG triplet, and the 3' guanine residue of a GGGG quartet. The results of this study demonstrate that treatment of cultured cells with a high concentration of thymidine can result in G.C --> A.T transition mutations that occur preferentially at the 3' guanine residue of a run of two or more adjacent guanines. Guanine residues flanked on their 3' side by other guanine residues are severalfold less mutable by thymidine than are guanine residues flanked on their 3' side by a different base. This study demonstrates a sequence-specific mode for thymidine-induced mutations and suggests implications for mutagenesis in vivo.