EXPRESSION OF THE NEURON-SPECIFIC ENOLASE GENE BY RAT OLIGODENDROGLIAL CELLS DURING THEIR DIFFERENTIATION

We have examined the regulation of neuron-specific gamma-enolase gene (NSE) expression in oligodendrocytes at various steps of their differe ntiation/maturation. We have demonstrated for the first time that NSE is expressed in oligodendroglial cells in vitro and in vivo, and only at a certain stage of differentiation. A heterogeneity of the gamma su bunit was observed in cultured oligodendrocytes and the same one was f ound in adult rat brain. The level of gamma mRNA increased when precur sor cells differentiated into oligodendrocytes. By contrast, no signif icant change in alpha-enolase gene expression was observed. High NSE ( gamma gamma and alpha gamma) enolase activity was detected in cultured oligodendrocytes. Treatment with basic fibroblast growth factor, whic h stimulates the proliferation of oligodendrocyte precursor cells and reversibly blocks their differentiation, resulted in lower alpha gamma - and gamma gamma-enolase activities in these cells, but it enhanced a lpha alpha-enolase activity slightly. These data indicate that gamma-e nolase gene expression is associated with the differentiation of the o ligodendrocytes and that it is repressed in adult fully mature cells.