【摘要】 本研究用甲基硝基亚硝（MNNG）单独处理猴肾细胞后移去残余的诱变剂,然后将穿梭质粒pZ189（含有靶基因supFtRNA基因）引入细胞中复制,并在大肠杆菌MBM7070中筛选突变子。结果显示:0.2μmol/L MNNG处理组的突变频率较自发突变频率增加了3.1倍,而0.2和2μmol/L MNNG处理组点突变频率分别为12.2×10^-4（43/35376）和6.2×10^-4（22/35712）,比自发点突变频率2.1×10^-4（10/47741）分别增加了5.8倍和2.9倍,其卡方检验的P值均小于0.01。本研究首次证实了哺乳类细胞中存在着非定标性实变。更多还原

【Abstract】 The intact pZ189 DNA were introduced into monkey kidney vero cells to replicate, which had been pretreated with N-menthyl-N’-nitro-N-nitrosoguanidine (MNNG). The mutants were selected in E.coli MBM7070. The results showed that mutation frequency in the 0.2μmol/L MNNG pretreated cells increased by 3.1 times over the spontaneous mutation frequency. The scored point mutation frequencies were 12. 2× 10-4(43/35376) and 6.2×10-4(22/35712) in 0.2 and 2μmol/1 MNNG pretreated cells respectively. Thus 5.8 and 2.9-fold increases in point mutation frequencies were found when compared with the spontaneous mutation frequency of 2.1 × 10-4(10 / 47741). Statistical analysis showed that the difference was significant(P< 0.01). This experiment demonstrate that nontargeted mutagenesis exists in mammalian cells.更多还原