Objective: To investigate the expression of the Cre recombinase mediated by human glial fibril-lary acidic protein (hGfap) gene promoter in mouse cerebellum. Methods: hGfapcre/Rosa26R transgenic mice were obtained by crossing hGfapcre transgenic mice with Rosa26R Cre reporter mouse strain. X-gal staining was applied to observe the distribution of Cre recombinase in their cerebellum at embryonic days 12.5, 13.5, 14.5, 16.5 and week 3 after birth. In addition, immunohistochemical staining with cell specific antibodies, Blbp (as-troglial marker), NeuN (neuronal marker) and Calbindin (Purkinje cell marker) was used to identify the cells expressing Cre recombinase indicated by X-gal staining. Results: At embryonic day 13.5, X-gal-positive cells appeared in the rhombic lip (rl) and further expanded to the entire cerebellum until embryonic day 16.5. Three weeks after birth, X-gal-positive cells coexpressed Blbp and NeuN, but did not express Calbindin. Conclusion: The expression of the Cre recombinase mediated by hGfap gene promoter appears in the rhombic lip as early as embryonic day 13.5, and the Cre recombinase mainly expresses in astrocytes (including Bergmann glial cells) and granular cells, not presents in the Purkinje cells. These results indicate that the GFAP-positive cells eventually differentiate into astrocytes (including Bergmann glia) and granular cells in the development of cerebellum, but do not generate into Purkinje cells.%目的:探讨以人胶质纤维酸性蛋白(hGfap)基因启动子介导的Cre 重组酶在小鼠小脑中的表达.方法:将hGfapcre 转基因小鼠与Rosa26R 转基因鼠杂交得到hGfapcre/Rosa26R 基因型小鼠,分别在胚胎12.5 、13.5 、14.5 、16.5d 和出生后3 周,取小脑组织切片行X-gal 染色观察Cre 重组酶分布;另外,出生后3 周的小脑组织切片同时使用细胞种类特异性抗体Blbp(星形胶质细胞标记物)、NeuN(颗粒细胞标记物)、Calbindin(浦肯野细胞标记物)进行免疫组织化学染色鉴定X-gal 染色阳性细胞类型.结果:胚胎13.5d,小脑菱唇开始出现X-gal 染色阳性细胞;此后Cre 重组酶表达范围进一步扩大,至胚胎16.5d,X-gal 染色阳性细胞可覆盖整个小脑;在出生后3 周,X-gal 染色阳性细胞可以和Blbp 及NeuN 共标记,和Cal-bindin 不能共标记.结论:以hGfap 基因启动子介导的Cre 重组酶最早在胚胎13.5d 的菱唇开始表达,并且Cre 重组酶主要表达于星形胶质细胞(包括Bergmann 胶质细胞)和颗粒细胞,不表达于浦肯野细胞,表明在小脑发育过程中以GFAP 为标记物的胶质细胞主要向星形胶质细胞(包括Bergmann 胶质细胞)和颗粒细胞分化,不向浦肯野细胞分化.
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