Nogo-A is a myelin-associated neurite outgrowth inhibitor and an antigen for monoclonal antibody IN-1

The capacity of the adult brain and spinal cord to repair lesions by axonal regeneration or compensatory fibre growth is extremely Limited. A monoclon al antibody (IN-1) raised against NI-220/250, a myelin protein that is a po tent inhibitor of neurite growth, promoted axonal regeneration and compensa tory plasticity following lesions of the central nervous system (CNS) in ad ult rats(1-4). Here we report the cloning of nogo A, the rat complementary DNA encoding NI-220/250. The nogo gene encodes at least three major protein products (Nogo-A, -B and -C), Recombinant Nogo-A is recognized by monoclon al antibody IN-1, and it inhibits neurite outgrowth from dorsal root gangli a and spreading of 3T3 fibroblasts in an IN-1-sensitive manner. Antibodies against Nogo-A stain CNS myelin and oligodendrocytes and allow dorsal root ganglion neurites to grow on CNS myelin and into optic nerve explants. Thes e data show that Nogo-A is a potent inhibitor of neurite growth and an IN-1 antigen produced by oligodendrocytes, and may allow the generation of new reagents to enhance CNS regeneration and plasticity.