Assembly and Maintenance of the Axonal Cytoskelton in Cultured Neurons

在所有细胞中，一组复杂的纤维状蛋白质组合形成了支撑和组织细胞及其组件的支架；这种支架被称为细胞骨架。大脑细胞的细胞骨架特别复杂；每个脑细胞(神经元)由两个不同的区域组成，每个区域都有单独划分为该区域的独特成分。虽然近年来在了解轴突细胞骨架的组成方面取得了重大进展，但由于在完整的大脑中研究这些过程的内在困难，控制其初始组装的因素以及细胞骨架稳定性的实现仍然没有得到很好的文献记载。为了克服这些困难，一个涉及细胞培养中的神经元的模型系统已经被开发出来，用于操纵大脑中发生在发育和成熟期间的形成事件。这些细胞在培养中不断繁殖，从而为实验提供了几乎无限的来源。在明确的化学处理之后，这些细胞停止增殖，并精心设计长轴突样过程，其中包含组成大脑轴突细胞骨架的大部分蛋白质。将通过已建立的和新开发的分子生物学、生化、免疫学和电子显微镜分析来开发这一模型系统，以检查伴随轴突细胞骨架组装的事件序列。从这些分析中获得的结果将阐明调节轴突生长和稳定的关键事件，这是神经系统有序发展和维持所需的。

Within all cells a complex array of fiber-like protein assemblies form a scaffold for the support and organization of the cell and its components; this scaffold is referred to as the cytoskeleton. The cytoskeleton of cells of the brain is especially complex; each brain cell (neuron) is composed of two distinct regions, and each of these regions has unique components which are partitioned into that region alone. While significant progress has been made in recent years towards understanding the composition of the axonal cytoskeleton, factors governing its initial assembly, as well as the attainment of cytoskeletal stability, remain less well documented due to the inherent difficulties of studying these processes in the intact brain. To surmount these difficulties, a model system involving neurons in cell culture has been developed for manipulating the formative events in the brain that occur during development and maturation. These cells multiply continuously in culture and thus provide a virtually unlimited source for experimentation. Following defined chemical treatments, these cells cease multiplying and elaborate long axon-like processes that contain most if not all of the proteins comprising the axonal cytoskeleton of the brain. Exploitation of this model system by both established and newly- developed molecular biological, biochemical, immunological and electron microscopic analyses to examine the sequence of events accompanying the assembly of the axonal cytoskeleton will be investigated. The results obtained from these analyses will elucidate events critical for mediating axonal outgrowth, and stabilization, required for orderly development and maintenance of the nervous system.