CONTROL OF SCHWANN CELL GROWTH

雪旺氏细胞的增殖部分是由相互作用控制的 用合适的轴突，无论是在体内还是体外。 雪旺细胞 组织培养中的细胞群保持静止，除非与轴突接触 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。 这一观察结果表明， 第一次，获得足够的神经突有丝分裂原供应， 纯化和表征。 我们建议净化特定的 存在于PC-12大鼠嗜铬细胞瘤细胞表面的蛋白质， 对雪旺细胞有促分裂作用。 初步观察表明， PC-12有丝分裂原在功能上类似于存在于细胞表面的有丝分裂原。 背根神经节神经突表面。 这些有丝分裂原不同于 以前鉴定的多肽激素（有丝分裂原），并被推测为 在正常发育过程中调节雪旺细胞的生长。 纯化的蛋白质将被表征，并且这些蛋白质之间的相互作用将被确定。 具有雪旺细胞表面受体的特异性生长因子将 被研究。 3 '，5'-环磷酸腺苷蛋白的作用 雪旺细胞促有丝分裂反应中的磷酸化和离子流 这些神经突有丝分裂原和其他生长因子，从以前的已知 影响许旺细胞增殖的工作，将进行研究。

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.