PROGRAMMED CELL DEATH IN THE NERVOUS SYSTEM

我们已经研究了神经系统中的程序性细胞死亡， 细胞凋亡的生化机制。 为了接近紧张的 系统，更敏感和原位的方法来识别细胞 细胞程序性死亡 我们开发了两种新方法， 在显微镜下识别凋亡细胞。 (1)我们发现 胸腺细胞程序性细胞死亡可以在形态学上遵循 Nomarski光学和胸腺细胞死亡类似于神经元细胞 死亡 核分裂的形态学分析 我们测试细胞死亡是否是由于产生毒性因子或 因为失去了保护因素。 使用新的显微镜 用细胞凋亡的方法，发现异核体中有细胞核 遵循原始的和不同的父母细胞的命运，而不是 在细胞核之间转移凋亡或存活。 这种新方法还 使我们能够确定细胞凋亡的方法小脑颗粒 体外MPP+处理后的细胞死亡。 (2)我们还开发了 一种原位测量DNA链断裂的分子检测方法。 这 让我们能够检查正在经历神经退化的动物的大脑 缺血、MPTP治疗和发育期间的变化。 这 一种新的方法使我们能够确定细胞凋亡在细胞凋亡过程中所起的作用。 发展和在神经系统的各种疾病状态。 (3)我们已经开发了抗凋亡调节因子的单克隆抗体， Bcl-2、Bcl-x和Bax基因来探测细胞凋亡的调节， 体外和体内。 抗体显示Bax从细胞膜上迁移， 细胞质转化为线粒体膜。 为了探索Bax， Bcl-2和Bcl-xl在神经元中的运输--绿色荧光蛋白 已经被用来标记和跟踪细胞凋亡过程中的蛋白质。

We have studied programmed cell death in the nervous system and the biochemical mechanism of apoptosis in general. To approach the nervous system, more sensitive and in situ methods are needed to identify cells undergoing programmed cell death. We have developed two new methods to identify apoptotic cells under the microscope. (1) We have found that thymocyte-programmed cell death can be followed morphologically with Nomarski optics and that the thymocyte death resembles neuronal cell death. The morphological analysis of nuclear disintegration has allowed us to test whether cell death is due to production of a toxic factor or due to the loss of a protective factor. Using the new microscopic method to identify apoptosis, the nuclei in the heterokaryons were found to follow the original and distinct fate of the parent cells and not to transfer apoptosis nor viability between nuclei. This new method also allowed us to identify apoptosis as the method of cerebellar granule cell death after MPP+ treatment in vitro. (2) We have also developed a molecular detection method to measure DNA strand breaks in situ. This allows us to examine brains of animals undergoing neurodegenerative changes during ischemia, MPTP treatment, and during development. This new method has allowed us to determine the role apoptosis plays during development and during various disease states of the nervous system. (3) We have developed monoclonal antibodies against apoptosis regulatory genes Bcl-2, Bcl-x, and Bax to probe the regulation of apoptosis in vitro and in vivo. The antibodies reveal that Bax migrates from the cytosol to mitochondrial membranes during apoposis. To explore Bax, Bcl-2 and Bcl-xl trafficking in neurons the green flourescent protein has been used to tag and follow the proteins during apoptosis.