siRNA沉默DNA甲基化转移酶1基因干扰胎牛成纤维细胞增殖和凋亡

为阐明Dnmt1-siRNA对胎牛成纤维细胞（FBFCs）的影响，设计了3种针对Dnmt1的siRNA来转染FBFCs．结果显示：Dnmt1-siRNA3转染FBFCs 24,48,72 h后，Dnmt1 mRNA表达水平显著降低（P<0.01）．在转染后48 h，siRNA3对Dnmt1抑制效率达到近80%，Dnmt1-siRNA3处理的FBFCs增殖也受到显著影响，FBFC细胞活力下降、处于G₀/G₁过渡期细胞数量增多（P<0.05）．但Dnmt1-siRNA3组FBFC细胞的凋亡率也显著增加（P<0.05）．说明通过Dnmt1特异性siRNA能够有效地敲低FBFC中的Dnmt1 mRNA表达量，由于细胞周期分布变化，siRNA处理后FBFC作为核供体能提高SCNT的效率．

Interference of DNA Methyltransferase 1 Gene Silenced by siRNA on Fetal Bovine Fibroblast Cell Proliferation and Apoptosis

To determine the effects of siRNAs targeting Dnmt1 on fetal bovine fibroblast cells (FBFCs), three siRNAs against Dnmt1 were designed for transfection into FBFCs. The results showed that Dnmt1-siRNA3 significantly reduced the mRNA expression level at 24, 48 and 72 h (P<0.01). At 48 h post-transfection, the inhibitory efficacy of siRNA3 against Dnmt1 reached nearly 80%. Dnmt1-siRNA3 treatment of FBFCs also significantly inhibited their proliferation, reduced cell viability and arrested more cells in the G₀/G₁ transition (P<0.05). However, Dnmt1-siRNA3 increased the number of apoptotic cells (P<0.05). This study demonstrated that specific siRNAs targeting Dnmt1effectively knocked down Dnmt1 mRNA expression in FBFCs,suggesting that the improved SCNT efficacy observed in the siRNA-treated donor cells might be partially due to changes in the cell cycle distribution.