Fig. 11. Extensive infiltration of labeled cells into the E15.5 Cx43-PCKO heart. (A) Short axis section through the RV infundibulum in an E15.5 P3pro-Cre⁺ control embryo showing labeled cells primarily limited to the area adjacent to the aortic valve. (B) Higher magnification of the infundibular myocardium in A (boxed) demonstrates only rare labeled cells. (C) RVOT of an E15.5 Cx43-PCKO embryo showing abundant labeled cells infiltrating the myocardium. (D) Higher magnification of the indicated region in C demonstrates numerous labeled cells in the myocardial wall and trabeculae. (E-H) Short axis sections through the RV infundibulum in a Wnt1-Cre⁺ control (E,F) and a Cx43-WCKO heart (G,H) reveal a limited distribution of labeled cells (arrows) similar to that seen in the P3pro-Cre⁺ control. F,H are higher magnifications of the boxed areas in E,G. Ao, aorta; RV, right ventricle. Scale bar: 400 µm for A,C,E,G; 50 µm for B,D,F,H.