Chemorepulsive axon guidance protein required for the development of spinal cord and forebrain commissures. Acts as a chemorepulsive guidance protein for commissural axons during development. Able to inhibit or repel neurite outgrowth from dorsal spinal cord and cortical explants in vitro. Binds directly to the neurites and growth cones. Expressed transiently during development of the brain and spinal cord, especially in the roof plate and the dorsal lip of the dermomyotome. Also present at the dorsolateral basement membrane of the spinal cord (at protein level). Belongs to the draxin family.