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目的 探索苯并a芘对k-ras基因的DNA损伤位点.方法 苯并a芘(AaP)染毒细胞提取基因DNA,采用依赖随机化末端连接物PCR(PCPCR)进行核酸杂交及产物测序.结果 BaP染毒剂量200 μmol/L检测到比-kras外显子2短的一条清晰的杂交条带;测序结果表明,linker与k-ras外显于2的第67位碱基C发生连接.结论 BaP可引起k-ras外显子2发生损伤,损伤位点在第66位碱基T,该损伤位点可能是其致癌作用靶点.“,”Objective To explore the DNA damage in k-ras, gene caused by BaP at the level of nucleic acid. Methods The TK6 cell was treated with BaP(benzo[a] pyrene) ,then its genomic DNA was amplified by RDPCR and detected by southern blot with the single-stranded probes of the exon 2 of k-ras gene. The PCR products were sequenced. Results A clear BaP-induced hybridized band shorter than the exon 2 of k-ras gene was observed. The sequencing analysis showed thatthe band was linked by the linker with 67th base C of the exon 2 of k-ras. Conclusion It is proved that Bap causes damage in the exon 2 of k-ras gene ,which is located in the 66th base T and maybe be the crucial cancerogenesis target of BaP.