Involvement of map kinase in the cyclic amp induction of myelin basic protein gene expression

Cyclic AMP is involved in the differentiation of oligodendrocyte and Schwann cell progenitors into mature myelin producing cells. The involvement of MAP kinases in this pathway was investigated in the D6P2T cell line. This cell line can be induced to display a differentiated phenotype characterized by myelin basic protein gene expression by increased cyclic AMP. BlockingMAPkinase activity with inhibitors of the activating kinase, MEK, by expression of a dominant negative MAP kinase or by expression of the MAPkinase inactivating phosphatase Mkp‐1 all blocked the activation of the myelin basic protein promoter in D6P2T cells. In addition, blocking MAP kinase activation during differentiation of an oligodendrocyte‐like cell line, CG4, also leads to inhibition of MBP expression. These findings suggest a role for MAP kinase in the cyclic AMP stimulated expression of the myelin basic protein gene during differentiation.