Figure 4. Timing of the innervation of the corneal epithelium is disrupted in Npn1^Sema−/− and Npn2^−/− mutants.

Cross sections of E15.5–E16.5 (A–B) Wild type, (C–D) Npn1^Sema−/−, and (E–F) Npn2^−/− corneas immunostained with TuJ1 and counterstained with DAPI. In wild type corneas, axons projection toward the epithelium at E15.5 (A) and innervate it at E16.5 (B). The corneal epithelium is innervated by E15.5 in Npn1^Sema−/− (C, asterisk) and Npn2^−/− (E, asterisk) mutant corneas. Scale bar: 50 µm.