IMMORTALIZED CELL LINES AND NEURAL TRANSPLANTATION

目前，人们致力于连续胞元的推导 可在组织培养中保持的用于神经的细胞系 作为原始细胞和组织的替代品的移植。我们有 用SV40大T抗原使原代培养的中枢神经系统细胞永生化， 使用方法选择具有神经元谱系的细胞。GABA- 产生纹状体细胞系和中脑细胞系 至碱性成纤维细胞生长因子，均已获得。然而，在大多数情况下，病毒 用于使细胞永生的癌基因干扰细胞周期 控件，以使永生化细胞不会最终变为 差异化。最终，有必要改进这些方法。 用来使神经元永生，这样细胞系就可以在 培养，并被诱导退出细胞周期，以允许终端 差异化。我们研究了在一定温度下永生化的细胞- 敏感形式的SV40大T抗原，发现这类细胞 即使在不允许的温度下也要继续分割，除非 提供附加刺激(例如，融合)以抑制细胞 成长。缺乏P53结合的SV40大T抗原的突变形式 活性，已被克隆以检测SV40大T的这些性质 使中枢神经系统神经元永生所需的抗原。备择 干预细胞周期控制的手段，使用直接传递 蛋白质因子和反义方法正在单独和在 与SV40大T突变体结合用于互补目的 加深对CELL所需步骤的理解 永生化，并改进生产永生化的方法 细胞系。

Efforts are currently being devoted to the derivation of continuous cell lines, which can be maintained in tissue culture, for use in neural transplantation as an alternative to primary cells and tissues. We have used SV40 large T antigen to immortalize cells from primary CNS cultures, using methods to select for cells with a neuronal lineage. GABA- producing striatal cell lines, and mesencephalic cell lines which respond to basic FGF, have been obtained. In most cases, however, the viral oncogenes that are used to immortalize cells interfere with cell cycle control, so that immortalized cells do not become terminally differentiated. Ultimately, it will be necessary to improve the methods for immortalizing neurons, so that cell lines can both be propagated in culture, and also induced to exit from the cell cycle to allow terminal differentiation. We have studied cells immortalized with a temperature- sensitive form of SV40 large T antigen, and found that such cells continue to divide even at the non-permissive temperature, unless provided with additional stimuli (e.g., confluence) to inhibit cell growth. A mutant form of SV40 large T antigen, which lacks p53 binding activity, has been cloned to examine those properties of SV40 large T antigen which are required for immortalizing CNS neurons. Alternative means of intervening in cell cycle control, using direct delivery of protein factors and antisense approaches, are being studied alone and in combination with SV40 large T mutants for the complementary purposes of developing an improved understanding of the steps required for cell immortalization, and improving the methods for producing immortalized cell lines.