Stimulation by nerve growth factor of specific protein synthesis in rat PC12 pheochromocytoma cells

Abstract

PC12 cells are a clonal line derived from a rat adrenal pheochromocytoma. When treated with ngm/ml levels of nerve growth factor PC12 cells stop dividing, extend long neurities and become electrically excitable. We have used polyacrylamide gradient gel electrophoresis in the presence of sodium dodecylsulphate to study the effects of nerve growth factor treatment on PC12 proteins. Treatment with nerve growth factor has very little effect on the relative abundances of major PC12 proteins. One consistent effect of the factor is induction of a polypeptide (designated p80) of apparent molecular weight 80,000. Induction of p80 is apparent within 1 day after addition of nerve growth factor and thus precedes neurite outgrowth; maximal induction is reached by 2–3 days of nerve growth factor treatment. Induction of p80 appears to be due to increased polypeptide synthesis rather than to increased stability of pre-existing molecules. Induction is rapidly reversible upon removal of nerve growth factor from cells pretreated with the factor. Induction and maintenance of p80 synthesis by nerve growth factor are selectively sensitive to camptothecin, an inhibitor of ribonucleic acid synthesis. Induction of p80 occurs normally in cells treated with nerve growth factor when process outgrowth is blocked by anti-microtubule agents or by growth in suspension. Induction is also normal when cells are treated with nerve growth factor in the absence of serum. The results suggest that transcription-dependent induction of specific protein synthesis is an early effect of nerve growth factor on PC12 cells and may play a role in bringing about nerve growth factor-induced changes in cell shape, division and physiological properties.