uvrA and recA mutations inhibit a site-specific transition produced by a single O6-methylguanine in gene G of bacteriophage phi X174.
uvrA and recA mutations inhibit a site-specific transition produced by a single O6-methylguanine in gene G of bacteriophage phi X174.
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uvrA和recA突变抑制噬菌体phi X174基因G中单个O6-甲基鸟嘌呤产生的位点特异性转变。
DOI：
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发表时间：
1985
影响因子：
11.1
通讯作者：
H. Borowy‐Borowski
中科院分区：
文献类型：
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作者：
R. Chambers;E. Sledziewska;S. Hirani;H. Borowy‐Borowski
使用定点突变，我们已经研究了O 6-甲基鸟嘌呤或O 6-正丁基鸟嘌呤位于噬菌体φ X174的基因G中的预选位点的体内诱变活性。设计实验使得通过从这些烷基化衍生物中的任一个靶向转变产生的噬菌体突变体将通过简单的噬菌斑测定来识别。将来自正常和修复缺陷细胞的球体转染，并筛选裂解物中的突变病毒。在正常修复的细胞中，携带甲基鸟嘌呤的DNA在15%的噬菌体中产生了预期的突变;携带丁基鸟嘌呤的DNA在0.3%的噬菌体中产生了相同的突变。在切除修复缺陷（uvrA）的细胞中，转换频率上升了8倍的O 6-丁基鸟嘌呤和下降了40倍的O 6-甲基鸟嘌呤。在重组缺陷的细胞（recA），过渡频率增加1.5倍，丁基鸟嘌呤和甲基鸟嘌呤减少了8倍。数据显示，甲基和丁基鸟嘌呤都在phi X174中产生定点转换;转换发生在recA细胞中;转换的频率受到recA和uvrA突变的影响; recA和uvrA突变以相反的方向改变甲基鸟嘌呤和丁基鸟嘌呤的转换频率。
Using site-specific mutagenesis, we have examined the mutagenic activity in vivo of O6-methylguanine or O6-n-butylguanine located at a preselected site in gene G of bacteriophage phi X174. The experiments were designed so that the phage mutant produced by a targeted transition from either of these alkylated derivatives would be recognizable by a simple plaque assay. Spheroplasts derived from normal and repair-deficient cells were transfected, and the lysates were screened for mutant virus. In cells with normal repair, DNA carrying the methylguanine produced the expected transition in 15% of the total phage; DNA carrying the butylguanine produced the same mutation in 0.3% of the phage. In cells deficient in excision repair (uvrA) the transition frequency went up by a factor of 8 for O6-butylguanine and down by a factor of 40 for O6-methylguanine. In cells deficient in recombination (recA), the transition frequency increased 1.5-fold for butylguanine and decreased by a factor of 8 for methylguanine. The data show that both methyl- and butylguanine produce site-directed transitions in phi X174; the transition occurs in recA cells; the frequency of the transition is influenced by both recA and uvrA mutations; the recA and uvrA mutations alter the transition frequency for methylguanine and butylguanine in opposite directions.