Fig. 2. Vascular disruption in embryos after Tie1-Cre induced inactivation of endothelial Lkb1. (A) Whole-mount immunofluorescence staining of Cre (red) and VE-cadherin (green) in E11.5 Tie1-Cre-positive yolk sac. (B,C) E11.5 wild-type (B) and Lkb1^lox/-, Tie1-Cre (C) yolk sacs. The Lkb1^lox/-, Tie1-Cre yolk sac is pale owing to a lack of blood in the vitelline vessels (arrow). (D,E) E11.5 wild-type (D) and Lkb1^lox/-, Tie1-Cre (E) embryos. Pericardial swelling (arrow) and dilated embryonic vessels (arrowheads) are apparent in the Lkb1^lox/-, Tie1-Cre embryo. (F,G) E12.5 wild-type (F) and Lkb1^lox/-, Tie1-Cre (G) embryos, demonstrating paleness and severe hemorrhaging in the mutant (arrowheads).