Fig. 5. Dorsally derived netrin 1 is important for the projection of sensory afferents. In situ hybridization for netrin 1 (A,B) and neurofilament immunohistochemistry (C,D) in transverse sections of the E12.5 spinal cord from wild-type (A,C) and Gli2 mutant (B,D) mice. (A) Netrin 1 is expressed in the floor plate and the ventral ventricular zone of the neural tube and at low levels in the dorsolateral spinal cord (arrowheads) in wild-type mice. (B) Netrin 1 expression in the ventral-most spinal cord is lost in Gli2 mutant mice (arrow), while the dorsolateral spinal cord expresses netrin 1 similarly to wild-type mice (arrowheads). (C,D) In both animals, the dorsal funiculus is correctly established in the marginal zone of the spinal cord with a sharp inner border (arrowheads). Scale bar: 200 µm in A,B; 100 µm in C,D.