SULFOGLUCURONYL (HNK-1) CARBOHYDRATE IN THE DEVELOPING NERVOUS SYSTEM

这个项目的主要目的是进一步了解细胞的作用， 糖脂（SGGL）上的表面磺基葡糖醛酸基碳水化合物（SGC）， 糖蛋白（SGGPs）在神经细胞识别过程中的作用。 我们 以前的研究表明，携带SGC的分子是瞬时的， 在发育过程中以阶段特异性方式在神经细胞上表达 而SGC本身似乎也参与了 直接参与细胞粘附的精确设计过程， 迁移 这些过程中的故障可能导致不适当的 神经系统发育和智力迟钝，如 几种神经细胞迁移障碍。 现时的建议是 研究了SGC的表达、调控和功能， 内源性凝集素识别神经细胞上的糖类 表面。 具体目标是：1. 表征SGC结合 蛋白质（SBPs），（凝集素）在发育中的神经系统。 三大 从脑中分离纯化了SBPs。 这些蛋白质将 进一步表征和它们的结合特异性， 将确定碳水化合物对SGGL和SGGP的影响。 的表达和 在神经系统的不同区域中， 将通过生物化学和免疫细胞化学建立发育 技术. SBPs在特定细胞粘附过程中的作用 将使用探测工具进行评估，例如适当的抗体， 修饰的蛋白质配体，在小脑细胞培养系统。 2. 了解SGGL的表达调控及其与细胞凋亡的关系， 生物学功能，关键调节酶GlcNAc-转移酶将 通过新颖的光亲和标记技术纯化。 的抗体 酶和mRNA探针将用于精确定位 在单细胞水平上合成SGGL。 3. 的基因 GlcNAc-Tr的克隆将为进一步的体内基因转染研究奠定基础。 SGC及其凝集素的免疫细胞化学和生物化学分析 将决定哪些分子参与了迁移过程 和神经细胞的成熟。 未成熟者的共培养 小脑颗粒细胞和星形胶质细胞将被用作模型系统， 确定碳水化合物在这一过程中的作用。 几个老鼠 突变体的异常细胞迁移和发育缺陷， 神经系统将被用作体内模型。 结果将产生 关于SGC及其凝集素在细胞内作用的基本信息 在发育中的大脑的相互作用和迁移，并将定义 参与细胞间相互作用过程的分子机制 和细胞分化。

The major goal of this project is to further understand the role of cell surface sulfogluguronyl carbohydrate (SGC) on glycolipids (SGGLs) and glycoproteins (SGGPs) in neural cell-cell recognition processes. Our previous studies indicate that SGC bearing molecules are transiently expressed on neural cells in a stage-specific manner, during development of the nervous system, and that the SGC itself appears to participate directly in the precisely choreographed processes of cell adhesion and migration. A malfunction in these processes could lead to improper nervous system development and mental retardation, as identified in several neuronal cell migration disorders. The present proposal is focused upon the expression, regulation and function of SGC and its endogenous lectins which recognize the carbohydrate on neural cell surfaces. The specific aims are: 1. To characterize the SGC binding proteins (SBPs), (lectins) in the developing nervous system. Three major SBPs from brain have been isolated and purified. These proteins will be further characterized and their binding specificity with respect to the carbohydrate on SGGLs and SGGPs will be determined. The expression and regulation of the SBPs in different areas of the nervous system during development will be established by biochemical and immunocytochemical techniques. The role of SBPs in specific cellular adhesion processes will be evaluated with probing tools, such as appropriate antibodies and modified ligands to the proteins, in cerebellar cell culture systems. 2. To understand the regulation of expression of SGGLs and their biological function, the key regulatory enzyme GlcNAc-Transferase will be purified by novel photoaffinity labeling techniques. The antibodies to the enzyme and mRNA probes will be used for the precise localization of the synthesis of SGGLs at single cell level. 3. The genes for GlcNAc-Tr will be cloned for future studies on gene transfection in vivo. Immunocytochemical and biochemical analyses of the SGC and its lectins will determine which molecules are involved in the process of migration and maturation of the neuronal cells. Co-cultures of the immature cerebellar granule cells and astroglia will be used as model system to define the role of the carbohydrate in this process. Several mouse mutants with abnormal cellular migration and developmental defects in the nervous system will be used as in vivo models. The results will generate fundamental information on the role of SGC and its lectins in cellular interaction and migration in the developing brain and will define the molecular mechanisms involved in the processes of cell-cell interaction and cell differentiation.