Figure 10

Spry1;Wnt1-Cre embryos show outflow tract defects at E9.5. (A, B) Whole mount β-gal staining of Cre-negative littermate control and Spry1;Wnt1-Cre E9.5 embryos. (A) WT shows intense β-gal staining of the outflow tract (white arrow) and branchial arches, indicating cells of NC origin. (B) Spry1;Wnt1-Cre E9.5 embryo, shows variable β-gal staining of the pharyngeal arches and reduced staining of the outflow tract (white arrowhead). (C, D) Sagittal sections of whole mount embryos with nuclear fast red counter-staining. (C) WT shows normal distribution of cardiac NCC within the outflow tract, with β-galactosidase positive NCC cells extending down to the bulbis cordis. Panel D, Spry1;Wnt1-Cre reveals outflow tract with reduced β-galactosidase positive NCC cells. In addition the first branchial arch, mandibular component, is greatly reduced in size relative to the WT. The outflow tract in Spry1;Wnt1-Cre embryos is shortened and does not adopt the spiral configuration as seen in the WT. (E,F) High power images of C,D; white boxed areas indicate field of view. (E) WT, black arrow indicates cardiac NCC contributing cardiac mesenchyme. (F) Spry1;Wnt1-Cre embryo, black arrowhead notes paucity of NCC in cardiac mesenchyme. FBA: first branchial arch, mandibular component. Data are representative of six embryos from each group.