VEGF-A₁₆₅ specifically promotes self-renewal of EB-derived erythroid progenitors. Individual primary colonies of either erythroid or granulo-monocytic origins derived from EBs differentiated for 15 days with cytokines+BMP-4 (-VEGF) or cytokines+ BMP-4+VEGF-A₁₆₅ (+VEGF) were aspirated from the methylcellulose at day 15, washed, dispersed, and replated into 2′CFU assays. The frequency of self-renewal capacity and its magnitude are shown in (A) and (B) respectively from both primary erythroid and CFU-GM, CFU-G, and CFU-M colonies (n = 3 experiments for each EB treatment and each type of primary colonies). SDs are represented by vertical bars.