Effects of BMP-4 and VEGF on the development of erythro-myeloid CFCs in EBs. A3-1 and E14 ES cell lines were differentiated for 7 days in the serum-free medium in the presence of 1.5 ng/mL BMP-4 or 15 ng/mL BMP-4 with or without 2 ng/mL VEGF or 20 ng/mL VEGF. EB cells were collected and subjected to erythro-myeloid CFC assays. Total-E (CFUE + BFU-E), CFU-M, CFU-n/mast, and CFU-mix were counted separately, and individual colony numbers were averaged over 3 to 4 independent experiments. The colony numbers are plotted/5 × 10⁴ total EB cells according to the VEGF concentration with the corresponding SD (vertical line). Open symbols are results from A3-1 ES cells, and closed symbols are from E14 ES cells. Squares indicate results obtained with 0 ng/mL BMP-4, circles indicate results obtained with 1.5 ng/mL BMP-4, and the diamond indicates results obtained with 15 ng/mL BMP-4.