Figure 5: OP9 coculture assay for ESC differentiation into mesoderm/hemangioblast cells. (a) Experimental set-up for OP9 cell-induced ESC differentiation. (b) At day 5 of ESC/OP9 coculture, we analyzed the formation of mesoderm islands and hemangioblast cells and observed a significant reduction in the percentage of FUBP1-deficient FLK1+ and FLK-1+/VE-Cad+ cells compared to NTC control cells. Three independent experiments were performed, each with 3 NTC and 5 Fubp1 knockout ESC clones. The data represent the mean values ± SD ().