Fig. 4. The optic nerves are thickened in the double-mutant mice. (A,B) Section of the wild-type (A) and Math3^–/–/NeuroD^–/– optic nerve (B) at E17.5. (C,D) NF staining of the wild-type (C) and Math3^–/–/NeuroD^–/– optic nerve (D) at E17.5. Scale bar: 50 µm. (E) The NF⁺ region of the optic nerve sections was quantified (n=3). The section of the double-mutant optic nerves is about 1.7-fold wider than that of the wild type.