Fig. 3.

Phenotype of Gα₁₃ endothelial-specific knockout and Gα₁₃^-/- embryos. All embryos are Tie2-Cre^Tg/o and had a heartbeat at the time of photography. (A–F) Gross appearance of Gα₁₃^+/+ embryos (A and D), Gα₁₃^flox/- embryos (B and E), and Gα₁₃^-/- embryos (C and F). At E9.5 (A–C), Gα₁₃^-/- embryos (C) were significantly delayed compared with control embryos (A); developmental arrest appeared to occur at ≈E8.5 as reported in ref. 17. Gα₁₃ endoKO embryos (B) had turned and appeared arrested at ≈E9.0. By E10.5 (D–F), >80% of Gα₁₃ endoKO embryos (E) were either dead or morphologically abnormal, and all Gα₁₃^-/- embryos (F) were dead or grossly abnormal. Dilated pericardial sacs, consistent with cardiovascular failure, were a prominent feature in both. (G–I) Whole-mount X-Gal staining of Tie2-Cre^Tg/o; ROSA26R embryos that were Gα₁₃^+/+ (G), Gα₁₃^flox/- (H), and Gα₁₃^-/- (I); embryos were collected at E9.5. Note that there is more primitive vascular plexus in the head of Gα₁₃ endoKO (H) and global Gα₁₃ nulls (I) compared with the control (G). (Scale bars: 1 mm.)