Gfi1 partially rescues Runx1^−/− deficiency. (A) Number of colonies generated in methylcellulose by iGfi1 Runx1^−/− FLK1⁺ cells either in absence or presence of dox. (B) FACS analysis of CD41/CDH5 of iGfi1 Runx1^−/− TIE2^hiKIT⁺CD41⁻ endothelial cells after 3 days of culture with or without dox. Numbers indicate percentages. (C) Bright field images of endothelial culture after 3 days with or without dox. Pictures were taken with a 10× objective. (D) Immunofluorescence analysis of CD41/CDH5 expression of iGfi1 Runx1^−/− hemogenic endothelial cells after 3 days of culture in absence (left panel) or presence (right panel) of dox. Blue corresponds to nuclear (DAPI), red to CDH5, and green to CD41 staining, respectively. These images are overlays of DAPI, CDH5, and CD41 staining. Pictures were taken with a 40× objective.