Percentages of apoptotic erythroblasts in culture.

Folate-deficient erythroblasts (FDCs) and normal control erythroblasts (NCs) were isolated from Friend virus–infected mice, cultured in folate-deficient medium (FDM) or control, folate-replete medium (CM), and processed for apoptosis and cell cycle phase analysis by flow cytometry as described in the legend to Figure 1. The percentage of TUNEL positive (apoptotic) erythroblasts at 0, 8, 20, 32, and 44 hours of culture are shown for FDC-CM (●), FDC-FDM (○), NC-CM (▴) and NC-FDM (▵). (A) CD₂F₁ mice and (B)p53 null mice. Results are ± 1 SEM for 5 separate experiments for CD₂F₁ FDCs, 3 separate experiments for CD₂F₁ NCs, and 4 separate experiments for p53 null FDCs. *Statistically significant differences in FDC-FDM.