Myelin-specific domain on the plasmalemma of oligodendroglia: differential expression in the rat and hypomyelinating mouse mutants jimpy and quaking

Abstract

Monoclonal antibody, 1A9, prepared against bovine white matter, recognizes a proteinaceous, myelin-specific domain in the CNS that is restricted to the surface of oligodendroglia in primary dissociated cell cultures. The antigen is not detected in the PNS or non-neural tissues. Antibody binding is abolished by heating, exposure to SDS and delipidation, indicating that a conformationally sensitive epitope is recognized. The antigen is present in tracts of developing white matter in rat cerebellum beginning at 5 days postnatally. In developing cultures of fetal rat brain the period of rapid onset for the phenotypic expression of 1A9 antigen is similar to that of galactocerebroside, corresponding to 2-4 postnatal days of age. The 1A9 antigen is not observed in white matter or cultured oligodendroglia of the hypomyelinating jimpy mutant mouse, but its expression is qualitatively normal in the quaking mutant. The possibility is raised that 1A9 may be the primary target of the jimpy mutation.