NR/CAM AND FORMATION OF NODE OF RANVIER

描述(逐字摘自申请者摘要)：有髓神经纤维 是通过跳跃传导有效传播脉冲的关键。 髓鞘在解剖学和生理学上被组织成纵向的节段 (节间)被Ranvier的节点中断。高浓度 的电压门控钠通道都位于节点上，并且特定 钾通道主要局限于结旁区域。这些节点 对沿神经的跳跃传导至关重要，但分子 人们对决定节点形成的信号知之甚少。最新研究 证明了免疫球蛋白中细胞黏附分子(CAM)的一个子集 超家族(即Nr-CAM和NeuroFasin)特异性地定位于 结节在其形成的早期阶段。 我们最近证明了一种重组形式的Nr-CAM可以干扰 背根神经节(DRG)共培养系统结节形成 神经元和雪旺细胞。结果有力地表明了Nr-CAM和 它的配体在结节形成中。因此，我们建议探索这些功能 Nr-CAM和能够与其相互作用的蛋白质，即Tag-1，Conactin， RPTPβ、神经束蛋白和锚蛋白在结节形成和维持中的作用 兰维尔的。 我们的第一个目标是确定Nr-CAM和 已知在神经元和雪旺细胞中与其相互作用的蛋白质 神经分化阶段。我们还将使用我们最近拥有的老鼠 产生的对于Nr-CAM蛋白搜索潜在的为空的 结节和神经的结构和发育的变化 传导。我们的第二个目标是分析Nr-CAM和蛋白质的作用 可以通过雪旺细胞-神经元共培养在结节形成过程中与之相互作用 系统。作为Fc融合蛋白和特异性抗体的CaM的重组形式 针对Nr-CAM及其绑定伙伴将被用来测试他们的能力 在共培养系统中扰动节点的形成。节点形成将是 通过对锚蛋白和钠通道的抗体染色进行分析 通常在培养的节点处聚集。我们的第三个目标是 确定Nr-CAM受体中与结节相关的特异性结合区域 形成并分析信号转导蛋白质聚集的分子机制 节点。 拟议的研究将阐明Nr-CAM的功能及其结合 PNS中节点开发的合作伙伴，还可以提供新的见解 中枢神经系统神经发育的分子基础。在未来，这样的 信息可能导致新的治疗策略，以防止伤害和 有髓神经受损并重新髓鞘的功能恢复 多发性硬化症。

DESCRIPTION (Verbatim from the Applicant's Abstract): Myelinated nerve fibers are critical for efficient propagation of impulses via saltatory conduction. Myelin is organized anatomically and physiologically into longitudinal segments (internodes) that are interrupted by the nodes of Ranvier. High concentrations of voltage-gated sodium channels are located in the node, and specific potassium channels are restricted primarily to the paranodal regions. The nodes are critical for saltatory conduction along the nerve, but the molecular signals that determine node formation are poorly understood. Recent studies demonstrated that a subset of cell adhesion molecules (CAMs) in the Ig Superfamily (i.e., Nr-CAM and neurofascin) are specifically localized to the node at early stages of its formation. We have recently demonstrated that a recombinant form of Nr-CAM can perturb node formation using a co-culture system involving dorsal root ganglion (DRG) neurons and Schwann cells. The results strongly indicate a role for Nr-CAM and its ligands in node formation. Therefore, we propose to explore the functions of Nr-CAM and proteins that can interact with it, i.e., TAG-1, contactin, RPTPbeta, neurofascin and ankyrin, in the formation and maintenance of the node of Ranvier. Our first goal is to determine the patterns of expression of Nr-CAM and proteins known to interact with it in neurons and Schwann cells at different stages of nerve differentiation. We will also use mice that we have recently generated that are null for the Nr-CAM protein to search for potential alterations in the structure and development of the node and in nerve conduction. Our second goal is to analyze the role of Nr-CAM and proteins that can interact with it in node formation using a Schwann cell-neuron co-culture system. Recombinant forms of CAMs as Fc fusion proteins and specific antibodies against Nr-CAM and its binding partners will be used to test their ability to perturb node formation in the co-culture system. Node formation will be analyzed by staining with antibodies against ankyrin and sodium channels that normally become clustered at the nodes in culture. Our third goal is to identify specific binding regions in the Nr-CAM receptors involved in node formation and to analyze molecular mechanisms that signal protein clustering at nodes. The proposed studies will clarify the functions of Nr-CAM and its binding partners in node development in the PNS and may also provide new insights into the molecular basis of nerve development in the CNS. In the future, such information may lead to new therapeutic strategies to prevent injury and restore function in myelinated nerves that become damaged and remyelinated in multiple sclerosis.