Fig. 7

smu mutations disrupt dorsoventral forebrain and retinal patterning, optic stalk formation and pituitary specification. (A) Expression of emx1 in wild-type (top) and smu^b641 mutant (bottom) embryos. emx1 expression expanded into ventral regions. (B) Expression of dlx2 in wild-type (top) and smu^b641 mutant (bottom) embryos. Ventral dlx2 expression was reduced in forebrain at the level of anterior and post-optic commissures; dorsal telencephalic expression was expanded. (C) Expression of pax2a in wild-type (top) and smu^b641 mutant (bottom) embryos. In smu mutants, pax2a expression was lost in optic stalk and ectopic (arrow) in hypothalamus. (D) Expression of pax6a in wild-type (top) and smu^b641 mutant (bottom) embryos. In smu mutants, pax6a expression was strongly reduced in thalamus. (E) Expression of pax6a expanded in ventral retina of smu mutants (bottom) compared with wild type (top). (F) Expression of pax2a in optic stalk (top, wild type) was lost in smu mutants (middle) and diencephalic cells expressed pax2a ectopically (arrow). An ectopic lens (arrow) developed in smu mutants, as shown in more ventral focal plane (bottom). (G) smu mutations affect specification of the pituitary. The anterior pituitary expressed lim3 in wild-type embryos (top). In place of the pituitary, an ectopic lens (arrow) formed in smu mutants (bottom). (H) Lens fiber cells differentiated in wild type (top), smu mutant ectopic (middle) and retinal lenses (middle, bottom) indicated by zl-1 (red). (A-D) Side views, dorsal towards the top, anterior towards left. (E,F) Dorsal view, anterior towards top. (G,H) Anterior view, dorsal towards top. 24 h. Scale bar in D: 100 μm in A-D; 40 μm in E; 50 μm in F (top); 25 μm in F (bottom); 60 μm in G; in H, 50 μm.