Nuclear control of neurite induction in neuroblastoma cells.

Induction of neurite formation in neuroblastoma cells by dibutyryl cyclic 3':5'-AMP (db-cAMP) or prostaglandin EI (PGE1) was enhanced after enucleation. Cells selected for resistance to db-cAMP were induced to form neurites by db-cAMP or PGE1 only after, but not before enucleation. Inhibition of protein synthesis inhibited neurite induction in nucleated, but not in enucleated cells, and enucleated cells were less sensitive to inhibition of neurite formation by concanavalin A (ConA). Colchicine, vinblastine and cytochalasin B (CB), compounds that interfere with the assembly of microtubules and microfilaments, inhibited induction in both types of cells. It is suggested that enucleation removes a nuclear inhibitor of neurite induction by db-cAMP and PGE1, and that neurite induction in nucleated cells requires that cAMP activates the assembly of microtubules and microfilaments and inactivates the nuclear inhibitor.