Erythroid defects in Fog^ki/ki CMP and MEP. (A) CMP, GMP, and MEP were cultured in the presence of EPO and SCF and scored at day 14. As control, WT and Fog^ki/ki GMP produced similar G and M progeny. Results are the average of 3 independent experiments. (B) BFU-E from CMP and MEP were categorized into large (> 50 clusters), medium (16-50 clusters), and small (5-15 clusters); n = 3. (C) Benzidine staining of representative large WT and Fog^ki/k BFU-E derived from MEP. Original magnification ×10.