Soluble myelin-associated glycoprotein-immunoglobulin G1 chimera protein promotes neurite outgrowth from mouse cerebellar neurons.

A soluble chimera protein consisting of the extracellular region of mouse myelin-associated glycoprotein (MAG) and the Fc region of human immunoglobulin G1, MAG-IgG, was prepared by transfecting an expression vector, BCMGSneo, containing the corresponding fused gene into mouse myeloma P3U1 cells. It was found that this MAG derivative promoted neurite growth of mouse cerebellar neurons in culture. In the presence of MAG-IgG the rates of neurite-bearing cells were significantly increased, and the neurites were distinctly lengthened. It was also observed that the anti-MAG monoclonal antibody inhibited this stimulation of neurite extension, supporting the specificity of the effect of MAG-IgG. These results suggest that soluble MAG derivative might act as a neurotrophic factor in the developing brain.