STRUCTURE/FUNCTION OF REGENERATING SYNAPSES

该项目现已进入第14个年头，其长期目标是 确定再生过程中所涉及的步骤和机制的顺序， 突触 它专注于神经肌肉突触，因为它 方便实验。 本提案中概述的实验 关于调节结构形成的机制 轴突末端和肌肉纤维的特化对突触的形成至关重要 传输 大多数实验都是针对定义 蛋白聚集蛋白的结构、功能和调控。 这些研究将 使我们能够检验神经肌肉接头处的聚集蛋白 介导神经诱导的乙酰胆碱受体聚集， 乙酰胆碱酯酶和其他组成突触的分子 肌肉纤维的特殊化。 一些研究也是针对 以确定肌肉诱导形成的分子基础， 轴突终末的突触特化。 具体目标是： 1.为了确定聚集蛋白在神经肌肉中的活性的细胞来源， 突触 2.鉴定和表征聚集蛋白的功能结构域。 3.研究聚集蛋白在发育和再生过程中的调控。 4.鉴定和表征诱导形成 再生轴突终末的突触前装置。 这些实验将涉及光学和电子显微镜， 免疫细胞化学和分子遗传学，并将在一个 各种神经肌肉制剂。 像这样的研究是必要的 了解神经肌肉疾病的细胞和分子基础 以及设计出增强神经肌肉功能恢复的方法 在创伤后。 因为大脑中的突触有突触前和突触后 与神经肌肉突触相似的专业化，这些 研究还可以提供关于CNS中涉及的机制的见解， 突触形成

The long-range objective of this project, now in its 14th year, is to define the sequence of steps and mechanisms involved in the regeneration of synapses. It has focused on the neuromuscular synapse because of its convenience for experimentation. The experiments outlined in this proposal concern the mechanisms that regulate formation of the structural specializations in axon terminals and muscle fibers crucial for synaptic transmission. Most of the experiments are directed toward defining the structure, function and regulation of the protein agrin. Such studies will enable us to test the hypothesis that agrin at the neuromuscular junction mediates the nerve-induced aggregation of acetylcholine receptors, acetylcholinesterase and other molecules that compose the synaptic specializations on muscle fibers. Some of the studies are also directed toward determining the molecular basis of the muscle-induced formation of synaptic specializations in axon terminals. The specific aims are: 1. To determine the cellular source of agrin active at the neuromuscular synapse. 2. To identify and characterize function domains in agrin. 3. To study the regulation of agrin during development and regeneration. 4. To identify and characterize molecules that induce the formation of presynaptic apparatus in regenerating axon terminals. These experiments will involve light and electron microscopy, immunocytochemistry and molecular genetics and will be conducted on a variety of nerve-muscle preparations. Studies such as these are requisite for understanding the cellular and molecular basis of neuromuscular disease and for devising ways to enhance restoration of neuromuscular function after trauma. Because synapses in the brain have pre- and postsynaptic specializations similar to those at the neuromuscular synapse, these studies may also provide insight as to the mechanisms involved in CNS synapse formation.