Fig. 1. Wild-type p53 protein levels are higher in the HA and HF revertants compared with parental HeLa cells, but p53 mRNA levels remain unchanged. A, 25 µg of nuclear extract protein were separated by SDS-PAGE. The p53 protein was detected by Western blot with p53-specific antibody (DO-1) and a horseradish peroxidase-conjugated secondary antibody and chemoluminescence. B, Northern blot analysis of total RNA extracted from HeLa (H), HA (A), HF (F), and Saos-2 (S) cells. The filter was probed with 32P-labeled p53 cDNA. C, ethidium bromide-stained filter used for Northern blot analysis.