EXPRESSION OF THE OLIGODENDROCYTE-MYELIN GLYCOPROTEIN BY NEURONS IN THE MOUSE CENTRAL-NERVOUS-SYSTEM

The oligodendrocyte-myelin glycoprotein (OMgp) is a 110-kDa glycosylph osphatidylinositol-linked protein that was initially identified as a m yelin-specific protein but whose precise function remains unknown, In this study, immunohistochemistry, western blots, in situ hybridization , and northern blots were used to determine the distribution of OMgp i n the mouse brain, OMgp is present in a concentration detectable on we stern blots in the brains of newborn mice, and its concentration gradu ally increases until day 24 of life, OMgp mRNA is also present in amou nts detectable on northern blots in the brains of newborn mice, and it s concentration gradually increases until day 21 of life, after which the concentration ion diminishes a little. Most of the OMgp in the mou se brain appears to be expressed in diverse groups of neurons, but it is particularly prominent in large projection neurons such as the pyra midal cells of the hippocampus, the Purkinje cells of the cerebellum, motoneurons in the brainstem, and anterior horn cells of the spinal co rd, However, OMgp is not confined to these cells and is expressed in c ells in the white matter as well. The OMgp gene is placed within an in tron of tile neurofibromatosis type I gene and on the opposite strand. This organization raises the possibility that there may be a relation ship between the functions of the products of the two genes, In suppor t of this possibility, we show that within the mouse CNS OMgp and neur ofibromin are expressed in the same cell types.