Fig. 2. Homozygous Vax2 mutant mice show coloboma in a significant percentage of cases. (A,B) Whole-mount eyes dissected from E16.5 foetuses. (A,B) Frontal views of wild-type (A) and mutant (B) eyes. The open optic fissure in the mutant is indicated by arrows in B. (C,D) Detection of laminin by immunohistochemistry in order to identify the basal lamina in frontal sections of wild-type (C) and Vax2^–/– (D) E12.5 embryos. Note how the basal lamina still persists in the mutant eye in the contact regions of the converging lips of the optic fissure (arrowheads), while in the wild-type eye it has completely dissolved. (E-H) Frontal sections, stained with Haematoxylin and Eosin, of wild-type (E,G) and Vax2 mutant (F, H) eyes at E16.5 (E,F) and P7 (G,H). No differences, apart from the presence of coloboma (arrowheads) can be detected in Vax2 mutant mice compared with wild-type animals in the organisation of retinal cell layers. re, retina; le, lens.