Dorsal Repulsive Axon Guidance Protein (DRAXIN)

The secreted protein draxin inhibited or repelled neurite outgrowth from dorsal spinal cord and cortical explants in vitro. Ectopically expressed draxin inhibited growth or caused misrouting of chick spinal cord commissural axons in vivo. Draxin knockout mice showed defasciculation of spinal cord commissural axons and absence of all forebrain commissures.Chick draxin mRNA was expressed transiently during development of the brain and spinal cord, especially in the roof plate and the dorsal lip of the dermomyotome. Mouse draxin mRNA was expressed in a manner similar to that of chick. Human draxin is comprised of 349 amino acids and contains a predicted signal peptide and 10 cysteine residues in the 125-amino acid conserved C-terminal region. It contains 1 N-glycosylation site, asparagine-258.