Fig. 10. Effect of p21 on the viability of wild-type p53-expressing and mock-transfected K562 clones. Cells transiently transfected with p21 or with control vector were seeded in culture medium at a concentration of 0.2 x 106 cells/ml and incubated at 32°C (i.e., the temperature permissive for the wild-type conformation of p53) for 4 days. Viability, as judged by trypan blue exclusion, as well as the total number of cells, was determined daily. Viability was always >90% on day 0. Mean values from three experiments are shown. , Mock 1/Control; , Mock 1/p21; , Mock 2/Control; , Mock 2/p21; , A4/Control; , A4/p21; , A10/Control; , A10/p21.