Functional analysis of carbohydrate chains involved in the differentiation and migration of cerbellar granule cells.

本研究的目的是分析小脑颗粒细胞特异性表达的神经节苷脂的功能。结果表明：（1）在大鼠小脑发育过程中，神经节苷脂的表达发生了显著变化，提示神经节苷脂可能在小脑皮质有序形成的早期调控中起重要作用;（2）神经节苷脂在原代培养的大鼠小脑中的表达也具有特异性。这些结果表明，几种神经节苷脂可能是鉴定原代培养的大鼠小脑细胞的有用标记物，特别是b系列神经节苷脂，如颗粒细胞的GD 2和GD 1b以及浦肯野细胞的O-Ac-LD 1。推导的氨基酸序列与乳脂小球膜糖蛋白相似。这些证据将有助于阐明神经节苷脂在中枢神经系统中的作用，特别是在颗粒细胞中表达的神经节苷脂的功能。

The aim of the project was to analyze the functions of gangliosides specifically expressed in cerebellar granule cells. We have obtained a number of significant findings as follows : (1) the expression of each ganglioside changed dramatically during the development of rat cerebellum, suggesting that specific gangliosides may play an imprtant role in regulating the early events responsible for orderly formation of cerebellar cortex ; (2) the expression of gangliosides in primary rat cerebellar cultures was also specific by using an immunohistochemical technique with monoclonal antibodies specific for gangliosides. These results suggested that several gangliosides may be useful markers for identifyiong cells in primary cultures of the rat cerebellum ; particularly b-series gangliosides such as GD2 and GD1b for the granule cells and O-Ac-LD1 for Purkinje cells ; (3) we isolated a cDNA clone encoded an O-Ac-disialoganglioside synthase by using a direct expression cloning from a rat cDNA library. The deduced amino acid sequence of the product was similar to the milk fat grobule membrane glycoprotein. These evidence would be useful for the elucidation of the role of gangliosides in the central nervous system, in particular, the functions of gangliosides expressed in the granule cells.