Zebrafish ryk loss of function phenotype. (A–F) Evaluating CE with markers. Dorsal view, anterior to the left of krox20 expression in uninjected (A), Ryk MO–injected (B), and Ryk MO co-injected with ryk RNA (C) embryos. Dorsal view, anterior to the top of myoD expression in uninjected (D; n = 32), Ryk MO–injected (E; n = 25), and Ryk MO co-injected with ryk RNA (F; n = 29) embryos. (D–F) The white dashed lines outline the lateral border of myoD domains. (G) Quantification of the CE phenotype, including embryos co-injected with Ryk MO and ryk ICD RNA (n = 30; 2.0 pmol Ryk MO; 50 pg ryk RNA; 50 pg ryk ICD RNA). Columns display the percentage of embryos at 10–11-somite stage with normal or defective CE index. (H–J) Morphological phenotypes at 24 hpf. Control (Ctrl.) MO–injected embryos (H) with even-spaced, V-shaped somites and Ryk MO (I)–, and Wnt5b MO–injected (J) embryos with reduced posterior A–P axis (double-headed arrow), and curved, tightly packed somites (white lines). Lateral view with anterior to the left. (K–N) Transverse central retina confocal images of 3-dpf huc:GFP transgenic embryos. Control (K) and Ryk MO (L)–, Wnt5b MO (M)–, and Ryk MO with ryk RNA (N)–injected embryos. The two organized sublaminae in the wild-type IPL (K, arrows) are less organized in both the Wnt5b (M, arrowhead) and Ryk (L, arrowhead) morphants. ryk RNA co-injection partially rescues Ryk MO–induced phenotype (N, arrows). Bars: (A–F) 150 µm; (K–N) 5 µm.