Knockdown and overexpression of FZD6 protein in zebrafish results in craniofacial defects. Both nonoverlapping morpholinos caused the same spectrum of craniofacial abnormalities. Only MO1-injected embryos are shown as an example. (A, D, G, J, and M) are uninjected control (UIC) embryos. (B, E, H, K, and N) show the phenotypes associated with knockdown of fzd6. (C, F, I, L, and O) show phenotypes associated with overexpression of fzd6. (A) UIC embryos at 24 hpf. (B) fzd6 MO-injected embryos at 24 hpf. (C) fzd6 mRNA-injected embryos at 24 hpf. (D) UIC embryos at 6 dpf. (E) fzd6 MO-injected embryos at 6 dpf. (F) fzd6 mRNA-injected embryos at 6 dpf. G-O show Alcian blue and alizarin red-stained embryos at 6 dpf. Jaw and palatal abnormalities due to fzd6 knockdown are shown (red arrows) in (K and N), respectively. Specifically in (K), arrows point to abnormal Meckel’s and ceratohyal cartilage in the lower jaw. In (N), arrows point to a reduced ethmoid palatal plate. Jaw and palatal abnormalities due to fzd6 overexpression are shown (red arrows) in (L and O), respectively. Specifically in (L), arrows point to abnormal Meckel’s and ceratohyal cartilage in the lower jaw. In (O), arrow points to a loss of the ethmoid plate in the palate.