Fig. 2

Depletion of frzb and fzd7a disrupts craniofacial development. (A–Y) Live embryo morphology (A–E) and Alcian blue cartilage stain (F-AB). Lateral view (A–J), ventral view (K–O), ventral view with lower jaw dissected away (P–T), taken at 10× magnification, scale bar 500 µm A–L, 100 μm M–P. View of the palate flat-mounted in ventral view (U–Y) and the lower jaw flat-mounted in lateral view (Z-AB), taken at 40× magnification. Anterior is to the left in all views. Wildtype embryos (A, F, K, P, U and Z), injected with frzb translation-blocking morpholino alone (MO) (B, G, L, Q and V), co-injection of frzb MO and non-complementary frzb mRNA (C, H, M, R, W and AA), embryos injected with fzd7a translation-blocking morpholino (MO) (D, I, N, S and X), and co-injection of fzd7a MO with non-complementary fzd7a mRNA (E, J, O, T, Y and AB) at 4.5 dpf. Normal craniofacial morphology (A) and craniofacial structures were seen in wildtype embryos, with normal lower jaw (F,K, Z) and palate (P,U). Knockdown of frzb and fzd7a produced smaller craniofacial structures grossly and narrow mouth openings (B, D). In frzb and fzd7a morphants, the proximal trabeculae form and converge at the midline, but fail to elongate and the palate does not form (Q, S). The chondrocytes in the leading edge of the trabeculae in frzb and fzd7a morphants appear dysmorphic and rounded and fail to adopt an organized intercalated pattern compared to wildtype (V,X). In frzb and fzd7a morphants, the lower jaw is absent and undetected by Alcian blue cartilage staining (G,I,L,N). Graphs summarize the representative phenotypes, where the total number of embryos scored for wildtype (red bar) and morphant phenotypes (blue bar) are shown with 5% error bars (AC,AD). Injection of non-complementary m RNA of frzb and fzd7a to rescue frzb MO and fzd7a, respectively, were statistically significant.