Structure and Function of Glionexin, An Insect Glial Glycoprotein

在神经系统中发现的一类细胞，虽然不是神经细胞本身，但被称为神经胶质细胞，因为它们早期被认为具有粘合细胞的作用。这些神经胶质细胞现在被认为对大脑正常功能的许多方面都很重要。神经胶质细胞及其相关产物参与了神经系统发育和组织的基本相互作用。昆虫被广泛用作发育的模型系统，在昆虫中，与胶质细胞相关的第一个抗原是一种称为GX的糖蛋白化合物，这种糖蛋白化合物在蟋蟀中被发现。GX的分布特征、时空表达特征和初步功能测试表明，GX作为粘附/识别分子参与神经发育。本研究利用抗体探针和微序列分析技术，筛选具有丰富遗传信息的胚胎蟋蟀和成年果蝇的基因cDNA文库，分离编码GX的基因并对其进行测序。该基因的鉴定将允许对这种化合物的功能进行新的测试，这反过来对理解在发育和再生过程中指导神经细胞生长的复杂相互作用将是重要的。这项工作将有助于更好地理解细胞粘附大分子的进化，并将对发育生物学和神经科学产生影响。

A class of cells found in the nervous system, though not nerve cells themselves is called glia, from their early presumed adhesive glue-like role to hold cells together. These glial cells are now known to be important for many aspects of normal function in the brain. Glial cells and their associated products participate in fundamental interactions which underline the development and organization of the nervous system. Insects are widely used as model system for development, and in insects the first antigen associated with glial cells was a glycoprotein compound called glionexin or GX, identified in the cricket. Features of its distribution, spatial and temporal expression, and preliminary functional tests suggested GX is involved in neural development as an adhesion/recognition molecule. This work uses antibody probes and microsequence analysis to screen genetic cDNA libraries from embryonic crickets and adult Drosophila flies, where we have a lot of genetic information, to isolate and sequence the gene encoding GX. Identification of the gene will allow new tests for function of this compound, which in turn will be important for understanding the complex interactions that guide nerve cell outgrowth during development and regeneration. The work may lead to better understanding of the evolution of cell adhesion macromolecules, and will have impact on developmental biology as well as neuroscience.