Identification of the Nogo inhibitor of axon regeneration as a Reticulon protein.
Adult mammalian axon regeneration is generally successful in the peripheral nervous system (PNS) but is dismally poor in the central nervous system (CNS). However, many classes of CNS axons can extend for long distances in peripheral nerve grafts. A comparison of myelin from the CNS and the PNS has revealed that CNS white matter is selectively inhibitory for axonal outgrowth. Several components of CNS white matter, NI35, NI250(Nogo) and MAG, that have inhibitory activity for axon extension have been described. The IN-1 antibody, which recognizes NI35 and NI250(Nogo), allows moderate degrees of axonal regeneration and functional recovery after spinal cord injury. Here we identify Nogo as a member of the Reticulon family, Reticulon 4-A. Nogo is expressed by oligodendrocytes but not by Schwann cells, and associates primarily with the endoplasmic reticulum. A 66-residue lumenal/extracellular domain inhibits axonal extension and collapses dorsal root ganglion growth cones. In contrast to Nogo, Reticulon 1 and 3 are not expressed by oligodendrocytes, and the 66-residue lumenal/extracellular domains from Reticulon 1, 2 and 3 do not inhibit axonal regeneration. These data provide a molecular basis to assess the contribution of Nogo to the failure of axonal regeneration in the adult CNS.
GrandPré
T
T
Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA.
Nakamura
F
F
Vartanian
T
T
Strittmatter
S M
SM
D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000502:physiology*; D002417:Cattle; D002455:Cell Division; D002460:Cell Line; D002490:Central Nervous System / Q000502:physiology*; D002642:Chick Embryo; D003001:Cloning, Molecular; D016384:Consensus Sequence; D004926:Escherichia coli; D006131:Growth Inhibitors / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009185:Myelin Proteins; D009416:Nerve Regeneration; D000070798:Nogo Proteins; D009836:Oligodendroglia / Q000378:metabolism; D016716:PC12 Cells; D051381:Rats; D011994:Recombinant Proteins; D017386:Sequence Homology, Amino Acid
D006131:Growth Inhibitors; D008565:Membrane Proteins; D009185:Myelin Proteins; D000070798:Nogo Proteins; C000603199:RTN4 protein, human; D011994:Recombinant Proteins; C000603197:Rtn4 protein, rat