Effects of inhibitors of glycoprotein processing on oligodendroglial differentiation in primary cultures of embryonic rat brain cells

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Abstract
The effects of N‐linked oligosaccharide processing inhibitors on oligodendroglial differentiation were examined in cultures of embryonic rat brain cells. The glucosidase inhibitors, 1‐deoxynojirimycin (dNM) and castanospermine, were found to have marked inhibitory effects on the developmental expression of oligodendroglial properties, i.e., sulfogalactolipid synthesis and 2′3′‐cyclic nucleotide 3′‐phosphohydrolase (CNP). On the other hand, the mannosidase inhibitors, 1‐deoxymannojirimycin (dMM) and swainsonine, had relatively little effects. Since both classes of inhibitors block the formation of complex‐type oligosaccharide chains as revealed by concanavalin A‐Sepharose affinity chromatography of the glycopeptides, complex oligosaccharides oligosaccharides do not seem to play a role in oligodendroglial differentiation. The results indicate instead that the early trimming reactions involving the removal of glucose residues by processing glucosidases may be critical for the functioning of specific glycoprotein(s) essential to oligodendroglial differentiation.