Fig. 1.
IL-3 regulation of apoptosis in the absence of p53. IL-3–dependent bone marrow cells from wild-type (A) or p53-null (B) mice, were plated at 2 × 105 cell/mL in a 24-well plate in the presence or absence of IL-3 after X-irradiation with 4 Gy as indicated. Cell viability was measured by trypan blue exclusion at the times shown. ([○] + IL-3; [□] + IL-3 + 4 Gy; [•] − IL-3; [▪] − IL-3 + 4 Gy.) (C) 5 × 106 wild-type or p53-null cells were analyzed for DNA fragmentation after X-irradiation as indicated with 4 Gy for 20 hours (wild-type) or 50 hours (p53-null), with or without IL-3, or after 6 hours of treatment with 10 μg/mL valinomycin in the presence of IL-3.