Myelin P0 Protein Expressed in C6 Cells Promotes Neurite Outgrowth

Protein zero (P0), a major glycoprotein in mammalian peripheral myelin, is a member of the immunoglobulin superfamily and plays a role in the formation and maintenance of peripheral myelin by homophilic adhesion.To clarify further its physiological roles, P0 protein was expressed in C6 glioma cells by transfection with P0 cDNA, and its neurite outgrowthpromoting activity was examined with cultured dorsal root ganglion neurons from newborn mice.Western blot analysis and immunological staining of the transformants revealed expression of P0 protein on the cell surface of transfected C6 cells.When the dorsal root ganglion neurons from 4-day postnatal mice were cultured on a feeder of C6 cells expressing P0, neurite outgrowth was markedly promoted compared with the neurons on cells not expressing P0.This neurite outgrowth promotion was specifically inhibited by the addition of an anti-P0 monoclonal antibody.The results suggest that P0 protein is involved in the neurite outgrowth in addition to its adhesive roles in the formation and maintenance of peripheral myelin.