The induction of a neural-specific gene, SCG10, by nerve growth factor in PC12 cells is transcriptional, protein synthesis dependent, and glucocorticoid inhibitable

Abstract

We describe features of the regulation of a neural-specific gene, SCG10, which is induced by nerve growth factor (NGF) during the neuronal differentiation of the rat pheochromocytoma cell line PC12. Induction of SCG10 mRNA occurs within 12–24 hr of exposure to NGF, is sustained in the continued presence of the neurotrophic factor, and involves a mechanism that is, at least in part, transcriptional. Unlike the rapid, transient transcriptional activations of genes such as c-fos, SCG10 induction requires ongoing protein synthesis, suggesting the participation of a de novo synthesized regulatory protein in mediating the effects of NGF on this gene. Although c-fos itself may play this role, its induction is clearly insufficient to cause an induction of SCG10. NGF, FGF, and, to a lesser extent, phorbol esters induced SCG10, whereas EGF and dibutyryl cAMP did not. In these characteristics, SCG10 induction appears to constitute a reliable molecular index of the transcription-dependent neuronal differentiation induced by NGF. Glucocorticoids, which inhibit NGF-induced neurite outgrowth from normal primary chromaffin cells, partially blocked SCG10 induction in PC12 cells. A reciprocal pattern of regulation by NGF and glucocorticoids was observed for tyrosine hydroxylase mRNA. These data suggest that environmental signals such as NGF may act on specific genes, both positively and negatively, to control the choice of alternative fates by developing neural crest cells.