Effect of exogenous ARF in retinoblastoma cells. (A) Immunofluorescence (red) staining for ARF protein in the cell line WERI-Rb1 four days after infection with adenovirus encoding human ARF cDNA (adARF) or gfp (adgfp). Blue, DAPI stain. (B) Western Blot analyses of p53 and its transcriptional targets BAX, MDM2 and p21 in cells treated with adARF or adgfp four days after infection. (C) Relative number of viable cells after four days of treatment with adgfp or adARF. N = 3, t-test *P < 0.05.