EXTRACELLULAR MATRIX AND SCHWANN CELL DIFFERENTIATION

这项提案的长期目标是确定和 表征与雪旺细胞膜相关的分子 它们调节神经胶质细胞分化的早期阶段。 雪旺细胞分化的特征是一系列有序的 精心同步的阶段，由 神经元-神经胶质直接接触。最初，诱导雪旺细胞 繁殖并开始在光秃秃的轴膜上定义领土。 随后的形态变化导致神经胶质细胞的延伸 突起、轴突的包膜或髓鞘形成(S)和 伴随而来的是坚固的基板组织。因为神经胶质 分化对于正常的神经发育和 再生，实验的设计是为了识别和表征 介导雪旺病早期必备阶段的抗原 细胞分化。拟议中的实验检验了 假设分化的每个阶段都是由一种 与雪旺细胞膜相关的新分子S。 实验1将评估雪旺细胞的参与情况 膜相关抗原C4，在包膜过程中。 用免疫亲和的方法分离抗原，用于 生化特性和作为免疫原的用途。多克隆 抗体的使用带有新设计的体外微扰 功能干扰雪旺细胞早期阶段的研究 差异化。实验2利用新开发的 识别施万氏相关抗原的免疫方案 细胞膜。此外，筛选技术被用于 区分那些扰乱正常胶质细胞形态的抗原 和/或轴突的包膜。实验3 检验了一种膜相关硫酸肝素的假设 蛋白多糖介导雪旺细胞形态的组织 在被包裹的过程中。技术被用来 表位及其细胞位置的特征 参与维持细胞形态和相互作用 与环境的关系。实验4将利用间接 免疫组织化学方法比较时间进程和细胞 雪旺细胞抗原在体外和体外表达的分布 活体胚胎发生和再生过程中。这项提议将 识别调节雪旺细胞早期状态的分子 并因此开始通过以下方式表征这些机制 哪些轴突是被包裹的。

The long term goals of this proposal are to identify and characterize molecules associated with the Schwann cell membrane which mediate the early stages of glial differentiation. Schwann cell differentiation is characterized by an ordered series of carefully synchronized stages which are induced and promoted by direct neuron-glial contact. Initially, induced Schwann cells proliferate and begin to define territories on the bare axolemma. Subsequent morphological changes result in the extension of glial processes, the ensheathment or myelination of axon(s) and the concomitant organization of a robust basal lamina. Because glial differentiation is crucial for proper neural development and regeneration, experiments are designed to identify and characterize antigens which mediate the early, prerequisite stages of Schwann cell differentiation. The proposed experiments examine the hypothesis that each stage of differentiation is mediated by a novel molecule(s) associated with the Schwann cell membrane. Experiment #1 will evaluate the participation of a Schwann cell membrane-associated antigen, 'C4', in the process of ensheathment. Immunoaffinity methods are used to isolate the antigen for biochemical characterization and use as an immunogen. Polyclonal antibodies are used with newly designed in vitro perturbation studies to functionally disrupt the early stages of Schwann cell differentiation. Experiment #2 utilizes newly developed immunization protocols to identify antigens associated with Schwann cell membranes. Moreover, screening techniques are used to distinguish these antigens which perturb normal glial morphology and/or the ensheathment of axonal processes. Experiment #3 examines the hypothesis that a membrane-associated heparin sulfate proteoglycan mediates the organization of Schwann cell morphology during the ensheathment process. Techniques are used to characterize the cellular location of epitopes and their participation in maintenance of cell morphology and interactions with the environment. Experiment #4 will utilize indirect immunohistochemical methods to compare the time course and cellular distribution of Schwann cell antigens expressed in vitro and in vivo during embryogenesis and regeneration. This proposal will identify molecules that mediate the early states of Schwann cell differentiation and thus begin to characterize the mechanisms by which axons are ensheathed.