Fig. 2. Histological analysis of Pax6^EE/EE mice. All panels show Hematoxylin and Eosin stained 4 µm paraffin sections. E9.5 eyes from WT (A), Pax6^+/EE (B) and Pax6^EE/EE (C) embryos. This shows the optic vesicle (ov) in close contact with the surface ectoderm (se) that in the wild-type is thickened in the region of the lens placode (pl). In Pax6^EE/EE embryos, the nasal aspect of the placodal ectoderm is abnormally thin (arrow). E10.5 eyes from wild type (D), Pax6^+/EE (E) and Pax6^EE/EE (F) embryos. The optic cup (oc) and lens pit (lp) have formed through coordinated invagination of optic vesicle and lens placode. In Pax6^EE/EE embryos, the lens pit and optic cup are small. Pax6^+/EE embryos show an intermediate phenotype. E11.5 eyes from wild type (G), Pax6^+/EE (H) and Pax6^EE/EE (I) embryos. In the wild type, the lens vesicle (lv) has separated form the surface ectoderm (se). In the homozygous mutant, the lens vesicle is small and remains attached (red arrowhead). Heterozygotes have an intermediate phenotype (red arrowhead). E12.5 eyes from wild type (J), Pax6^+/EE (K) and Pax6^EE/EE (L) embryos. At this stage, primary fiber cells (pfc) have extended from the posterior lens vesicle towards the lens epithelium (le) in both wild type and mutant embryos, but the homozygous mutant lens is small with a persistent lens stalk (red arrowhead). The optic cup in Pax6^EE/EE embryos is marginally smaller than in wild type. Again, heterozygotes have an intermediate phenotype. E17.5 eyes from wild type (M), Pax6^+/EE (N) and Pax6^EE/EE (O) embryos. In eyes of this stage, both primary and secondary fiber cells have differentiated in all genotypes. A smaller lens is apparent in homozygotes and a local invagination of the corneal epithelium (red arrowhead) indicates a persistent lens stalk. Morphologically, pseudostratification in the retina appears unaffected.

Return to article