Figure 9

Spry1;Wnt1-Cre embryos exhibit cardiac outflow tract malformations and associated cardiac defects. (A, B) Cre-negative littermate control (WT) and Spry1;Wnt1-Cre (Spry1) embryos at E18.5; gross photos of heart. A, shows WT with normal outflow tract and aortic arch architecture, and B shows abnormal outflow tract architecture with a persistent truncus arteriosus (TA) and aortic arch anomalies. (C, D) WT and Spry1;Wnt1-Cre E18.5 embryos, coronal sections through the thoracic cage stained with H&E. (C) normal outflow tract with aortic valve (AV) and pulmonary valve (PV) and an intact interventricular septum (black arrow). (D) Spry1;Wnt1-Cre enbryo shows a persistent truncus arteriosus (TA) which overrides the interventricular septum (IS) with a membranous ventricular septal defect (black arrowhead). (E, F) WT control and Spry1;Wnt1-Cre E14.5 embryos sectioned through the thoracic cage. (E) WT normal cardiac architecture. (White arrow denotes left ventricular outflow). (F) Shows a double outflow right ventricle with the aorta (Ao) arising from the right ventricle (white arrowhead) and the pulmonary outflow tract, which is narrowed with a malformed pulmonary valve and ventricular septal defect (not shown). LV-left ventricle, RV-right ventricle, RA-right atrium, LA-left atrium, Ao-aorta, PT-pulmonary trunk, DA-dorsal aorta, TA-truncus arteriosus, Aa-aortic arch, PV-pulmonary valve, AV-aortic valve, BC-brachiocephalic artery, LC-left common carotid artery, LS-left subclavian artery, Asterix *-ductus arteriosus. Data are representative of six embryos from each group (WT and Spry1) from two independent litters.