Figure 4.

The p53-GAr chimeras are stable in tumor cells with accelerated p53 degradation. The HPV18-E6-positive cervix carcinoma cell line HeLa (A) or the Mdm2-overexpressing osteosarcoma cell line U2OS (B) was transiently transfected with ^FLAGp53 or the indicated ^FLAGp53-GAr chimeras. After 16 h, the cells were incubated with 60 μg/ml of cycloheximide, and cell extracts were harvested after the indicated incubation times. Expression of p53 was detected by Western blotting with a monoclonal anti-p53 antibody. The endogenous p53 (end.) and ectopic ^FLAGp53 products are indicated.