CONTROL OF SCHWANN CELL GROWTH

雪旺细胞的增殖在一定程度上受相互作用的控制 体内和体外都有合适的轴突。纯雪旺细胞 组织培养中的种群除非与轴突接触，否则保持静止 或来自轴突的膜碎片。我们最近发现， 雪旺细胞对培养神经元突起的促有丝分裂反应 当这些细胞与PC-12细胞接触时，也会发生 建立大鼠嗜铬细胞瘤细胞系。这一观察结果提供了 第一次，获得足够的轴突有丝分裂原 纯化和表征。我们建议提纯特定的 PC-12大鼠嗜铬细胞瘤细胞表面存在S蛋白 对雪旺细胞是有丝分裂的。初步观察表明， PC-12有丝分裂原在功能上类似于存在于 背根神经节突起表面。这些有丝分裂原与 以前发现的多肽激素(有丝分裂原)，并被推定为 在正常发育过程中调节雪旺细胞的生长。 将对纯化的蛋白质进行表征，并研究这些蛋白质之间的相互作用 雪旺细胞表面有受体的特异性生长因子将 被研究。3‘，5’环一磷酸腺苷蛋白的作用 雪旺细胞有丝分裂反应中的磷酸化和离子通量 对这些轴突有丝分裂原和其他生长因子的作用，从以前的 影响雪旺细胞增殖的工作，将被调查。

The proliferation of Schwann cells is, in part, controlled by interaction with appropriate axons, both in vivo and in vitro. Schwann cells in pure populations in tissue culture remain quiescent unless in contact with axons or membrane fragments derived from axons. We have recently found that the mitogenic response of Schwann cells to the neurites of cultured neurons also occurs when these cells come in contact with PC-12 cells, an established rat pheochromocytoma cell line. This observation provides, for the first time, access to an adequate supply of the neurite mitogen for purification and characterization. We propose to purify the specific protein(s) present on the surface of PC-12 rat phechromocytoma cells which is mitogenic for Schwann cells. Initial observations indicate that the PC-12 mitogen is analogous in function to the mitogen present on the surface of dorsal root ganglia neurites. These mitogens are different from previously identified polypeptide hormones (mitogens), and are presumed to serve to regulate the growth of Schwann cells during normal development. The purified proteins will be characterized and the interaction of these specific growth factors with receptors on the surface of Schwann cells will be studied. The role of 3', 5' cyclic adenosine monophosphate, protein phosphorylation and ion fluxes in the mitogenic response of Schwann cells to these neurite mitogens and to other growth factors, known from previous work to influence Schwann cell proliferation, will be investigated.