Fig. 2. Sufu^-/- mutants exhibit an open neural tube and abnormal cardiac looping. Gross morphology of wild-type (A) and Sufu^-/- (B,C) embryos at 9.5-10.5 dpc. Cross-sections of 9.5-10.5 dpc wild-type (D) and Sufu^-/- (E,F) embryos stained with Hematoxylin and Eosin. Sufu^-/- embryos had an open neural tube and failed to complete turning. The descending aorta was dilated (E,F). Some Sufu^-/- embryos had a normal D-looped heart (B,E) whereas others displayed an inverted L-looped heart (C,F). Higher magnification of the cardiac region is shown in G (normal looping) and H (inverse looping). Red arrows display the direction of cardiac looping. da, descending aorta; ht, heart; nt, neural tube.