FMRP促进胚胎小鼠大脑皮层神经元发育与迁移

Fragile mental retardation protein promotes the development and migration of the cortical neurons in embryonic mouse

目的观察脆性X智力障碍蛋白(FMRP)对胚胎小鼠大脑皮层神经元发育与迁移的影响。方法应用基因定点突变技术构建pEGFP-FMRPmutant与pEGFP质粒;采用子宫内胚胎鼠电极针刺技术将质粒转染到胚胎鼠侧脑室并用PCR和Southern analysis技术鉴定FXS小鼠类型;尼氏染色与荧光免疫组织化学双染技术分析大脑皮质各细胞层神经元分布数目并进行统计学分析。结果尼氏染色确定胚胎小鼠大脑皮质各细胞层,荧光免疫双染共聚焦显示实验组胚胎小鼠侧脑室区/侧脑室下区(VZ/SVZ)(1.76倍,P=0.035)和中间带(IZ)(1.71倍,P=0.002)表达标记EGFP(绿色)的神经元数目比对照组显著增多;实验组小鼠VZ/SVZ(5.48倍,P=0.006)和IZ(2.16倍,P=0.043)同时表达标记EGFP(绿色)和Nestin(红色)神经元数目亦比对照组显著增多。结论 FMRP促进胚胎小鼠大脑皮层神经元前体细胞的分化发育与迁移,FMRP缺乏时神经元发育及迁移滞后。

Objective To investigate the effect of Fragile X mental retardation protein（FMRP） on the development and migration of the cortical neurons in embryonic mouse. Methods Plasmids containing FMRPmt-pEGFP or pEGFP were created and delivered into the lateral ventricle of mouse by utero-electroporation before genotyping by PCR and Southern analysis. Then Nissl staining and immunofluorescence staining were conducted to evaluate the number of progenitor cells in different neocortex layers. The values were statistically analyzed. Results Nissl staining showed the obvious neocortex layers. Immunofluorescence staining showed that the number of pEGFP positive cells in the VZ/SVZ （ventricle zone/subventricle zone, 1.76-fold,P =0.035） and IZ （intermediate zone, 1.71-fold, P=0.002） was significantly higher in FMRP group than in normal control. The double immunofluorescence staining revealed that the number of nestin/EGFP-positive cells in the VZ/SVZ （5.48-fold, P=0.006） and in the IZ （2.16-fold,P =0.043） was higher in FMRP group than in normal control significantly. Conclusion FMRP promotes the neurons development and migration, the absence of FMRP delays the development and migration in embryonic mouse.