Cytogenetic characteristics and p53 gene status of human teratocarcinoma PA-1 cells in 407-445 passages

To study why the human teratocarcinoma cell line PA-1 maintains a stable ne ar-diploid karyotype even after it has been cultured for more than twenty y ears, p53 gene status of the cell line in 407-445 passages were investigate d in detail by DNA sequence analysis and a yeast function status assay. Dir ect sequence analysis of RT-PCR products showed both wild and mutated bands (p53 codon 239 mutation). Consistent with the above results, the functiona l assay showed that one allele of the p53 gene was active (wild), while the other was inactive (mutant). In addition, the PA-1 cells expressed the p21 protein to a lesser extent than normal human fibroblasts. Though many line s of evidence have shown that mutant p53 works dominant-negatively, our res ults suggest that mutation in a p53 allele alone can not induce cytogenetic instability.