Tie-2-Cre;Ets1^−/−;Ets2^fl/fl embryos have obvious defects in angiogenesis. (A) MORE;Ets1^−/−;Ets2^fl/fl (left) and Tie2-Cre;Ets1^−/−;Ets2^fl/fl (right) E11.5 embryos with edema and hemorrhage. Bars, 0.5 mm. (B) PCR products from DNA extracted from yolk sac of E11.5 Tie2-Cre;Ets1^−/−;Ets2^fl/fl (lane 1), Ets2^fl/+ (lane 2), or Ets2^fl/KO (lane 3) mice. (C) PECAM (red) and Ets2 (green) antibody staining of cryosections from E11.5 embryos of genotype Ets1^−/−;Ets2^fl/fl (top panels) or Tie2-Cre;Ets1^−/−;Ets2^fl/fl (bottom panels). The third panel is the merged image of PECAM and Ets2 staining. Bars, 50 μm (D) PECAM antibody staining in whole mount of Tie2-Cre;Ets1^−/−;Ets2^fl/fl embryos and Ets1^−/−;Ets2^fl/fl controls, as indicated. Representative data are shown, including pericardium (E11.5, first left panel set), back (E10.5, second middle panel set), and head (E10.5, third right panel set). Arrowheads highlight examples of vessel branching in control embryos that are absent and/or abnormal in the double-mutant embryos. Bars, 0.25 mm.