SYNAPSIN REGULATION OF NEURONAL CYTOSKELETAL DYNAMICS

有两种突触蛋白基因，突触蛋白I和II，其表达是 与神经元细胞骨架的动态重组相关， 轴突分化和突触形成：突触素的过度表达 加速分化，耗竭阻碍分化。 这 这项提案的重点是确定肌动蛋白和微管的作用， 神经元分化过程中突触蛋白的结合特性。（一） 为了确定一种突触蛋白的缺失如何影响 改变细胞骨架动力学，免疫细胞化学 和差示提取技术将用于表征 突触蛋白和细胞膜结合蛋白亚细胞定位 在野生型和突触蛋白敲除小鼠的原代神经元培养物中。 (2)肌动蛋白和微管结合结构域在细胞凋亡中的作用 突触蛋白的营养作用将由（a）定位 这些结构域使用覆盖、共沉淀和聚合测定 筛选突变重组突触蛋白，（B）测定 突变突触蛋白诱导非神经元细胞的形态学变化， 和（c）确定突变体是否可以拯救形态学和 突触蛋白敲除小鼠培养物中的发育缺陷。(3)的 突触素分子间/分子内缔合在调节肌动蛋白中的作用 并研究微管结合。 这些研究将 增强我们对控制神经元的机制的理解， 分化

There are two synapsin genes, synapsin I and II, expression of which is associated with dynamic reorganization of the neuronal cytoskeleton, axon differentiation, and synapse formation: overexpression of synapsin accelerates differentiation and depletion retards differentiation. This proposal focuses on determining the role of the actin- and microtubule- binding properties of the synapsins during neuronal differentiation. (1) To determine how depletion of one synapsin affects the distribution of the other synapsin and alters cytoskeletal dynamics, immunocytochemical and differential extraction techniques will be used to characterize the sub-cellular localization of synapsin and cytoskeletal-binding proteins in primary neuronal cultures from wildtype and synapsin knockout mice. (2) The role of the actin- and microtubule-binding domains in the trophic actions of the synapsins will be determined by (a) localizing these domains using overlay, co-sedimentation, and polymerization assays to screen mutant recombinant synapsins, (b) determining the ability of mutant synapsins to induce morphological changes in non-neuronal cells, and (c) determining if mutants can rescue morphological and developmental defects in cultures from synapsin knockout mice. (3) The role of synapsin inter/intra-molecular association in regulating actin- and microtubule-binding will be investigated. These studies will enhance our understanding of the mechanisms that control neuronal differentiation.