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目的 :探讨人类恶性畸胎瘤PA 1细胞株染色体特性及p5 3基因的状态及其意义。方法 :采用G带核型分析、DNA碱基序列分析等方法对经 2 0余年 4 0 7～ 4 4 5继代培养的PA 1细胞株染色体核型及p5 3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 2倍体的核型 ,30代以后的细胞由于第 15号染色体与 2 0号染色体间的相互易位形成了M 1及M 2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 2个带 (p5 3密码子 2 39突变 )。结论 :人卵巢恶性畸胎瘤PA 1细胞株经 2 0年的继代培养后 ,1个p5 3等位基因发生错义突变 ,另 1个仍然是野生型的。仅 1个p5 3等位基因发生突变 ,不足以引起细胞的染色体不稳定性。因此 ,研究PA 1细胞稳定核型的维持结构 ,在确定有关染色体的稳定性与不稳定性的基因的方面是非常重要的。
Objective: To investigate the chromosomal characteristics and the status of p5 3 gene in PA 1 human malignant teratoma and its significance. Methods: The chromosome karyotype and p5 3 gene status of PA 1 cell lines cultured from 4 0 7 to 4 4 5 after more than 20 years were analyzed by G-band karyotype analysis and DNA base sequence analysis. RESULTS: More than 80% of the PA1 cell lines remained nearly diploid karyotypes. After 30 generations, the M 1 and M 2 marker chromosomes were formed due to the mutual translocation between chromosome 15 and chromosome 20. RT-PCR product DNA directed sequence analysis showed two bands with wild-type and two mutations (p39 codon239 mutation). CONCLUSION: After 1 year of subculturing PA 1 cell line of human ovarian malignant teratoma, one p5 3 allele has a missense mutation and the other is still wild-type. Only one p5 3 allele mutation, not enough to cause cell chromosome instability. Therefore, investigating the maintenance of PA 1 cell-stable karyotypes is important in determining the genes involved in the stability and instability of chromosomes.