LAMININ AND FIBRONECTIN IN PERIPHERAL NERVE DEVELOPMENT

这项拟议研究的长期目标是了解 细胞外基质(ECM)蛋白纤维连接蛋白(FN)和层粘连蛋白(LAM) 在外周神经系统(PNS)发育中。ECM分子调节 胚胎发育过程中细胞的形态、分化和运动。在 PNS、ECM分子似乎参与了神经脊的迁移和 神经肌肉接头的发育和再生。的生长锥体 从神经管或外周神经节移行的神经纤维 底物途径也可能含有粘性分子。这个 粘附性糖蛋白FN和LAM是很好的介导者 PNS细胞迁移和分化的特定阶段，由于其 胚胎的定位及其与三叉神经节细胞的体外相互作用。首先，什么？ FN和LAM功能区介导神经元-基质黏附和 轴突延伸？民阵的两个地区有这些活动，并有 揭示了神经元类型与FN分子的特定相互作用。 LAM的功能区不那么明确，但也可能促进细胞 类型特定的行为。将使用FN和LAM的蛋白水解性片段， 结合抗体，评价1)功能差异 在FN与细胞相互作用的区域之间，2)细胞表面 硫酸乙酰肝素介导了其中的某些相互作用，以及3)每个 结构域有助于完整的FN对细胞行为的调节 分子。此外，生长锥体粘连在轴突形成中的作用 对FN片段的扩展进行研究。第二，FN和LAM怎么样(和 每个区域的特定区域)由发育中的PNS中的细胞使用？方法 将通过免疫细胞化学揭示时间和空间的联系 细胞与细胞外基质分子之间的相互作用；2)免疫组织化学标记 确定产生LAM和FM的细胞及其生长的近似性 3)用抗体抑制神经突起的延伸。 自然产生的基质和体内的相关作用的探讨 每个分子。第三，FN和LAM的定义区域如何有助于 神经脊细胞的迁移和分化？做冠状细胞 亚群附着于和/或移动到这些区域的某些区域 处于特定分化阶段的分子？相反，DO定义了 细胞外基质分子区域对CREST细胞的分化作用 亚群？(将与詹姆斯·韦斯顿博士合作进行研究 Lab)具有细胞-细胞外基质相互作用的背景和现在的工具 对我们来说，我们将能够准确地评估国民阵线和 负责PNS开发的LAM。

The long-range goal of the proposed research is to understand the roles of the extracellular matrix (ECM) proteins fibronectin (FN) and laminin (LAM) in peripheral nervous system (PNS) development. ECM molecules regulate cell shape, differentiation, and movement during embryogenesis. In the PNS, ECM molecules appear to be involved in neural crest migration and development and regeneration of neuromuscular junctions. Growth cones of nerve fibers migrating from the neural tube or peripheral ganglia traverse substrate pathways that are also likely to contain adhesive molecules. The adhesive glycoproteins FN and LAM are good candidates for mediating particular stages of PNS cell migration and differentiation, due to their locations in embryos and interactions with PNS cells in vitro. First, what functional regions of FN and LAM mediate neuron-substratum adhesion and neurite extension? Two regions of FN have these activities and have revealed neuronal type-specific interactions with the FN molecule. Functional regions of LAM are less well-defined, but may also promote cell type-specific behavior. Proteolytic fragments of FN and LAM will be used, in conjuction with antibodies, to evaluate 1) the functional distinctions between the regions of FN that interact with cells, 2) whether cell surface heparan sulfate mediates certain of these interactions, and 3) how each domain contributes to mediation of cell behavior by the intact FN molecule. In addition, the role of growth cone adhesion in neurite extension on FN fragments will be studied. Second, how are FN and LAM (and specific regions of each) used by cells in the developing PNS? Approaches will be 1) immunocytochemistry to reveal temporal and spatial associations between cells and ECM molecules, 2) immunolabeling for TEM and SEM to identify the cells producing LAM and FM and their proximity to growth cones, and 3) inhibition, with antibodies, of neurite extension on naturally-occurring matrices and in vivo to probe the relative roles of each molecule. Third, how do defined regions of FN and LAM contribute to migration and differentiation of neural crest cells? Do crest cell subpopulations attach to, and/or move upon, certain regions of these molecules at particular stages of differentiation? Conversely, do defined regions of ECM molecules exert differentiative effects on crest cell subpopulations? (To be studied in collaboration with Dr. James Weston's lab) With our background in cell-ECM interactions and the tools now available to us, we will be able to evaluate precisely the roles of FN and LAM in PNS development.