Fig. 3

Wnt signaling pathway expression in the developing squid eye. A–G Wnt gene expression at stage 23. Based on expression, Wnt7, Wnt8, Wnt2, Wnt11, and Prot Wnt are possible candidates to signal the anterior segment. A Lateral, whole-mount expression of Wnt8. A’ Dorsal retina expression of Wnt8. Location of the section indicated by the orange line in B. A” Central section lacking retina expression. Location of the section indicated by the red line in B. B Cartoon of the lateral whole-mount embryo at stage 23. Orange and red lines correspond to the location of the two sections shown in A, A’, and C, C’. D–G Expression of other Wnt homologs in central sections. H–K Expression of Frizzled receptors at stage 23. Fz1/2/7 shows asymmetric expression and Fz5/8 shows specific exclusion from the central cup cells. J and K are lateral view of the whole mount expression. J” and K” are cartoons of expression in J’ and K’ respectively. Gradients of expression show intracellular asymmetries in the anterior segment. Black dotted line in sectioned images shows the perimeter of the retina. L–O Anterior segment and lens morphology after Wnt agonist treatment (LiCl). Embryos were cryosectioned and stained with Sytox-green (nuclei, cyan) and phalloidin (F-actin, magenta). L and L’ Control and LiCl agonist treatments started at stage 21, treated for 24 h and fixed immediately. M and M’ Control and Wnt agonist (LiCl) treatments started at stage 23 for 24 h and fixed immediately. N and N’ Control and Wnt agonist (LiCl) treatments started at stage 21, treated for 24 h and allowed to recover for 48 h and fixed. O and O’ Control and Wnt agonist (LiCl) treatments started at stage 23, treated for 24 h and allowed to recover for 48 h and fixed. Arrowhead highlights the lens. P–S In situ hybridization of anterior segment markers after 24-h control and LiCl treatments starting at stage 23. Phenotypes are characterized as Type I (mild) and Type II (severe). The white dotted line outlines the eye in the lateral image. The number of eyes scored in control and the two phenotypes is found in LiCl-treated animals in the top right corner. Scale for all lateral whole-mount view images is 200 μm. Scale for all sectioned images is 50 μm. Anterior is down in all sectioned images. White dotted line in whole mount images identifies the perimeter of the eye. m, mantle; a, arms; aco, anterior chamber organ; mo, mouth; r, retina; l, lens