Journal of Neuroscience, Vol 6, 3348-3354, Copyright © 1986 by Society for Neuroscience
Oligodendrocyte cell adhesion molecules are related to neural cell adhesion molecule (N-CAM)
S Bhat and DH Silberberg
The glycoproteins responsible for calcium-dependent oligodendrocyte
aggregation were purified and characterized. Using detergent extraction,
lentil-lectin-Sepharose 4B affinity chromatography, and preparative gel
electrophoresis, 3 proteins were purified to apparent homogeneity, with
relative Mrs of 120,000, 140,000, and 180,000. The aggregation assay showed
that all 3 proteins had the ability to block antibody-mediated inhibition
of oligodendrocyte aggregation. The 120,000 protein was the most active of
the three. Antisera were raised in rabbits to these 3 individual proteins.
Western blot analyses showed that all three antisera recognized 120,000,
140,000, and 180,000 proteins, which indicated that the proteins were
related. Western-blot analyses of cultured oligodendrocytes and purified
rat myelin showed only the 120,000 protein. Immunoprecipitation of
iodinated membrane proteins of cultured oligodendrocytes also indicated the
presence of only the 120,000 Mr protein. Deglycosylation of the 120,000
protein by N-glycanase resulted in a 110,000 protein. The immunoblot
pattern suggested some similarities between oligodendrocyte adhesion
molecules and the neural cell adhesion molecule (N-CAM). Therefore, the
120,000, 140,000, and 180,000 Mr proteins were compared to N-CAM by
Western-blot analysis, immunofluorescence staining, and by
immunoprecipitation. The results suggest that oligodendrocytes contain a
120,000 membrane glycoprotein that is related to N-CAM.