Fig. 2

Morphogenetic movements in the eyes are affected and cell death is increased in the optic lobes of chk. Cross-sections of the head of wild-type (A–C) and chk^w (D–F) embryos at the 5-somite stage (A, D), 16-somite stage (B, E) and Prim-5 (C, F). At the 5-somite stage, the evagination of the optic lobes is visible in wt embryos (red arrows in panel A) but not in chk (D). At the 16-somite stage, the flattening of the medial layer (delimited by the red arrows in panels B and E) has started in wt embryos (B). Instead, an increase in cell death is observed in the optic lobes of chk (E′). In wt, the RPE is completely flattened and starts differentiating around 24 hpf (arrow in C). In contrast, the lenses are smaller in chk at the Prim-5 stage (arrowheads in C and F), the prospective RPE is not pigmented (F), and the cells in the outer most layer of the optic cup in chk die (F&prime). Similarly, chk embryos (J–L) stained with acridine orange exhibit increased cell death in the eyes (arrowheads) and in the tectum (arrows) at the 20-somite stage, when compared to wt (G–I). In spite of the abnormal morphogenetic movements, extraocular mesenchyme is associated to the optic cups of chk (black arrows in panels B and F). The images are lateral views with the anterior oriented to the left. (I, L) Overlay of the DIC images (G, J) and the fluorescence images (H, K). Prim-5, primordium stage 5. Other abbreviations like in Fig. 1.