NEUROMUSCULAR JUNCTION DEVELOPMENT

神经肌肉接头(NMJ)是一种特殊的突触 运动神经元和肌肉纤维。NMJ由一系列 神经突起、细胞外基质和肌管的发育变化 涉及无数的生物事件，包括细胞增殖和 过程的死亡、展开和收回与膜的发展 专业化认证。目前，突触发生的确切机制仍然存在。 不清楚；然而，人们普遍认为神经释放的因素 (例如，Agin、ARIA、黏附分子)可以促进和协调 进程。与这一假设一致的是，已经证明了 神经源性乙酰胆碱受体诱导活性分子 (ARIA)诱导某些NMJ特异性蛋白的表达(例如 培养的肌管中的乙酰胆碱受体、钠通道)。通过 ARIA的生化关联及作用机制分析 肌肉，我们希望朝着我们的长期目标取得进展 了解NMJ的复杂发展变化是如何 精心设计，并提供对影响 神经肌肉系统。 更具体地说，这里提出的实验将使我们能够识别 与ARIA有生物化学关联的分子，并表征 他们的联系的性质。这项分析将需要使用生化 确定亲和力和可能的结构选择性的方法 针对候选蛋白的ARIA以及鉴定新的ARIA结合 蛋白质存在于培养的细胞以及肌肉和神经中。 此外，我们还将研究ARIA影响 突触的形成，无论是在基因表达水平还是在基因表达后 先前存在的蛋白质的翻译修饰以及尝试 阐明ARIA用来实现这些的信号通路 改变。ARIA在人类神经肌肉中发挥重要作用的可能性 将通过高度分离和鉴定来调查疾病 人类ARIA和ARIA同源物的信息遗传标记- 受体基因和疾病分析被认为是很好的候选者 病理生理基础或遗传图谱位置。

The Neuromuscular Junction (NMJ) is a specialized synapse between the motor neurons and muscle fibers. NMJ's are formed by a series of developmental changes in neurites, extracellular matrix and myotubes involving a myriad of biological events including cell proliferation and death, elaboration and retraction of processes and development of membrane specializations. Currently, the exact mechanism of synaptogenesis remains unclear; however, it is generally accepted that factors released by nerves (e.g. Agrin, ARIA, adhesion molecules) may facilitate and co-ordinate the process. Consistent with this hypothesis, it has been demonstrated that a neurally derived molecule named Acetylcholine Receptor Inducing Activity (ARIA) induces the expression of certain NMJ-specific proteins (e.g. Acetylcholine receptors, Sodium channels) in cultured myotubes. By analyzing the biochemical associations and mechanism of actions of ARIA in muscle, we hope to make progress toward our long term goal of understanding how the complex developmental changes at the NMJ are choreographed as well as provide insights into diseases affecting the neuromuscular system. More specifically, the experiments proposed here will allow us to identify molecules that are biochemically associated with ARIA and characterize the nature of their association. This analysis will entail using biochemical methods to determine the affinity and possible structural selectivity of ARIA towards candidate proteins as well as identifying novel ARIA-binding proteins present in cultured cells as well as muscle and nerve. Additionally, we will examine the mechanisms by which ARIA influences synapse formation, both at the level of gene expression and post- translational modification of preexisting proteins as well as attempt to elucidate the signaling pathways utilized by ARIA to achieve these changes. The possibility of ARIA being important in human neuromuscular diseases will be investigated by isolating and characterizing highly informative genetic markers for the human homologues of ARIA and ARIA- receptor genes and analyzing diseases considered good candidates based on patho-physiological grounds or genetic map position.