α粒子诱发转化人支气管上皮细胞BEP2D中p53基因的突变特点

Mutation of p53 gene in human bronchial epithelial cells BEP2D induced by α-particles

目的 观察α粒子诱发BEP2D细胞转化过程中p5 3基因的改变。方法 聚合酶链式反应 单链构象多态性分析 (PCR SSCP)。结果 分析发现在细胞转化过程中 ,p5 3基因发生重要改变 ,照射后早期传代细胞中 ,p5 3外显子 7就发生碱基突变 ,经酶切分析为 2 49密码子的改变 ,外显子5 6在照后 2 0代细胞内开始丢失 ,并经Southern杂交证实 ,以上改变均在转化过程中持续存在 ;而外显子 8 9未见变化。结论 p5 3基因外显子 5、6、7是α粒子对DNA损伤的重要靶位点 。

Objective\ To detect p53 gene mutation in BEP2D cells induced by α particles.Methods\ Analysis of genomic DNA from the transformed cells using PCR amplification and single strand conformation polymorphism (SSCP).Results\ SSCP and restriction enzyme analysis demonstrated a point mutation at codon 249 of tumor suppressor gene p53 which has been thought to be the “hotspot” of mutation in transformation induced by α particles.Southern blot analysis showed a deletion in exon 5/6 of p53 gene,but there was no mutation in the exon 8/9 of p53 gene.Conclusion\ p53 gene is the “target” of DNA lesions induced by α particles.It plays an important role in the process of transformation of bronchial epithelial cells induced by α irradiation.