人恶性畸胎瘤PA-1细胞染色体特性及其影响因素的探讨

目的:探讨人类恶性畸胎瘤PA-1细胞株染色体特性及其影响因素。方法:采用G带核型分析、DNA碱基序列分析及Western blot(蛋白印迹分析)等方法对经20余年407-445继代培养的PA-1细胞株染色体核型及p 53 基因状态进行了研究。结果:PA-1细胞株80%以上仍然保持近乎二倍体的核型,30代以后的细胞由于第15号染色体与20号染色体间的相互易位形成了M1及M2标识染色体。RT-PCR产物DNA定向序列分析显示具有野生及突变两个带(p53密码子239突变),Western blot 未检测出突变的p53基因蛋白,而p21蛋白的表达水平比正常成纤维细胞低。结论:人卵巢恶性畸胎瘤PA-1细胞株经20年的继代培养后,一个p53 等位基因发生错义突变,另一个仍然是野生型的。仅一个p53 等位基因发生突变,不足以引起细胞的染色体不稳定性。

Characteristics of chromosome of teratocarcinoma and its influence elements

AIM: To investigate the characteristics of chromosome of teratocarcinoma and its influence elements. METHODS: We used the methods of G-banded karyotype analysis, DNA basic sequence analysis and Western blot and the others, and studied the chromosome karyotype and the status of p53 gene of teratocarcinoma PA-1 cell line which had been cultured for 407-445 passages for 20 years. RESULTS: More than 80% PA-1 cells still maintained the near-diploid karyotype ,after passage 30 the cells appeared with M1 and M2 chromosomal markers because of a balanced translocation between chromosomes 15 and 20. DNA directional sequence analysis of RP-PCR products revealed that there were both wild and mutated band (p53 codon 239 mutation), Western blot did not detect mutational p53 gene protein,while p21 protein expression lower than that in normal human fibroblasts. CONCLUSION:Missense mutation of one of the p53 allele gene of PA-1 cells in human teratocarcinoma was detected after cultured for more than twenty years, which was not sufficient to induce the instability of the chromosome of cell line.