EXTRACELLULAR MATRIX AND SCHWANN CELL DIFFERENTIATION

该提案的长期目标是确定和 表征与许旺细胞膜相关的分子 其介导神经胶质分化的早期阶段。 雪旺细胞分化的特点是一个有序的系列 精心同步的阶段，诱导和促进， 神经元和胶质细胞的直接接触 最初，诱导的雪旺细胞 增殖并开始在裸露的轴膜上形成区域。 随后的形态学变化导致胶质细胞的延伸， 突起、轴突的鞘化或髓鞘形成以及 伴随组织的一个强大的基板。 因为神经胶质 分化对于适当的神经发育至关重要， 再生，实验旨在识别和表征 介导雪旺氏病早期先决阶段的抗原 细胞分化 拟议的实验检查 假设每个分化阶段都是由一个 与许旺细胞膜相关的新分子。 实验#1将评估施旺细胞的参与 膜相关抗原“C4”，在鞘化过程中。 免疫亲和方法用于分离抗原， 生物化学表征和作为免疫原的用途。 多克隆 抗体与新设计的体外扰动一起使用， 功能性破坏早期雪旺细胞的研究 分化 实验#2使用新开发的 免疫方案以鉴定与雪旺氏病相关的抗原 细胞膜 此外，筛选技术用于 区分这些干扰正常神经胶质形态的抗原 和/或轴突突起的鞘化。 实验#3 检验了一个假设，即膜相关的硫酸肝素 蛋白多糖介导雪旺细胞形态的组织化 在入鞘过程中。 技术用于 表征表位的细胞位置及其 参与维持细胞形态和相互作用 与环境。 实验#4将使用间接 免疫组化方法比较时间进程和细胞 体外和体内表达的雪旺细胞抗原的分布 在胚胎发生和再生过程中。 这项建议会 鉴定介导雪旺细胞早期状态的分子 分化，因此开始表征的机制， 哪些轴突被包裹。

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.