Figure 1. Cranial and cardiovascular defects in Wnt1creFak^flox/flox mice.

(A) Wnt1creFak^flox/flox mutants display a cleft palate (white arrowhead), with unfused palatal shelves. (B) Ventral view of E20 mutant and control skulls, stained with Alizarin Red (bone) and Alcian Blue (cartilage). Mutants show defective formation of the maxillary shelves (ms), palatine (p), and pterygoid process (pt) (yellow arrowheads). (C) E14.5 mutants show misplaced palatal shelves (ps) that failed to rotate or elevate (asterisk) and remained lateral to the tongue (tg). (D) Frontal view of P0 hearts injected with polymer casting material and cleared with Methyl salicylate, showing ventricular septal defects (VSD; arrowheads) in mutants. Insets show sections of these hearts stained with H&E. (E and F) Aortic arch artery phenotypes include a common brachiocephalic trunk (CBT; arrowhead in E) and interruption or coarctation of the aortic arch (IAA; arrowhead in F). Hearts in F were injected with blue polymer for better visualization of aortic arch patterning. (G–I) Outflow tract abnormalities in mutants include persistent truncus arteriosus (PTA) in G and H (yellow arrowheads) and overriding aorta (OA) in I (black arrowheads). (H and I) Paraffin-embedded cross (H) and frontal (I) serial sections from E20 hearts stained with H&E. Ao, aorta; ba, brachiocephalic artery; Ctl, control; lc, left carotid artery; Mut, Wnt1creFak^flox/flox mutant; n, nasal septum; Pt, pulmonary trunk. Original magnification, ×4 (A, B, and F); ×10 (C–E and G–I).