FIG. 4.

Ectopic c-myc expression interferes with p53-induced cellular differentiation. DP16.1/p53ts cells infected with c-myc or empty vector were incubated at 32°C for 0 or 36 h. Cells were stained for hemoglobin expression using DAF as described elsewhere (16). Stained cells were counted with a hemocytometer, and the proportion of hemoglobin-expressing cells was determined (number of blue cells/total number of cells). Results represent the means of three independent experiments ± the standard errors. Unsorted whole cell populations were used; infection efficiencies ranged from 40 to 60%.