【摘要】 观察Sim2基因对PC12细胞周期及细胞周期调控蛋白表达水平影响,初步阐明Sim2基因在Down综合征发病机制中的作用.以脂质体法将pcDNA3-mSim2真核表达载体瞬时转染PC12细胞;以RT-PCR方法检测mSim2基因在PC12细胞的表达;流式细胞仪观察细胞周期分布的变化;RT-PCR和免疫组织化学方法分别检测细胞周期调节蛋白E(cyclin E)和p27mRNA和蛋白水平的表达变化.RT-PCR结果显示,瞬时转染pcDNA3-mSim2的PC12细胞中有明显的mSim2mRNA表达;流式细胞仪检测发现,与对照组和空载体组相比,转染mSim2后,处于G0/G1期的PC12细胞百分比明显升高(P<0·01),而G2/M期的细胞百分比明显降低(P<0·01);在mRNA和蛋白水平上,转染mSim2的细胞细胞周期蛋白E表达较对照组明显降低;而p27的表达明显升高(P<0·01).以上结果表明,mSim2基因可能通过影响神经元前体细胞的增殖在Down综合征发病机制中发挥了重要作用.更多还原

【Abstract】 To observe the effect of mSim2 on the cell cycle and to explore the role of Sim2 in the pathogenesis of Down syndrome,the pcDNA3-mSim2 plasmid was transiently transfected into PC12 with Lipofectamine TM . The expression of mSim2 in PC12 was detected by RT-PCR. The effect of mSim2 on the cell cycle was observed by flow cytometer. The mRNA and protein expression of cyclin E and p27 were detected by RT-PCR and immunohistochemistry respectively. There was an elevated expression of mSim2 in the cells transfected with pcDNA3-mSim2. Upon flow cytometry, there were more cells in G₀/G₁ phase and fewer cells in G₂/M phase in pcDNA3-mSim2-transfected cells. The mRNA and protein expression of cyclin E decreased in the mSim2-transfected cells, while p27 expression increased （P<0.01）. The results indicated that mSim2 might play an important role in the pathogenesis of Down syndrome by inhibiting the cell cycle, which was related to the decreased cyclin E and increased p27 expression.更多还原