Figure 2.

Defective lens induction in Nf1^−/− mutants. (A–D) Pax6, Sox2 and AP2α, all essential lens determination factors, were appropriately expressed in the Nf1 presumptive lens ectoderm at E9.5 (arrowheads). (E–H) At E10.0, lens placode invagination was reduced in the Nf1 mutants. (I–P) At E10.5, although the lens vesicle was formed in wild-type controls, the Nf1 mutants were arrested at the lens pit stage. Nevertheless, expression of the lens determination genes Pax6, Sox2, AP2α, Six3 and periocular marker transcription factor Pitx2 were unaffected (arrowheads). le, lens ectoderm; ov, optic vesicle; lp, lens pit; lv, lens vesicle. Scale bars: 50 μm.