锌指核酸酶技术制备肌肉生长抑制素基因敲除的五指山小型猪成纤维细胞

敲除猪肌肉生长抑制素(Myostatin, MSTN)基因可能提高猪瘦肉率, MSTN基因敲除猪也可作为相关疾病的动物模型。文章利用锌指核酸酶(Zinc-finger nucleases, ZFNs)技术敲除五指山小型猪胎儿成纤维细胞MSTN基因, 为制备MSTN基因敲除猪奠定基础。ZFNs质粒或编码ZFNs的mRNA均能高效敲除MSTN基因, 使用ZFNs mRNA能直接得到MSTN+/-和MSTN-/-两种基因型的细胞克隆。DNA序列测定与分析发现, 细胞克隆的突变类型多为ZFNs作用靶位点处不大于10 bp的碱基插入或缺失(92.18 %); 氨基酸预测发现, 突变型MSTN基因的终止密码子常常提前出现。将MSTN基因敲除的细胞进行体细胞核移植(Somatic cell nuclear transfer, SCNT)发现, 胚胎体外早期发育潜力与野生型无显著差异, 表明这些细胞可用于后续MSTN基因敲除猪的制备。

Production of myostatin gene knockout Wuzhishan miniature pig fibroblasts with zinc-finger nucleases

Disruption of myostatin (MSTN) gene in pigs may improve porcine lean meat percentage (LMP), and create an animal model for certain human diseases. Using zinc-finger nucleases (ZFNs) technology, MSTN gene was deleted in Wuzhishan miniature pig fibroblasts by transfection of either ZFNs plasmids or ZFNs mRNA in high efficiency. Strikingly, ZFNs encoding mRNA could produce MSTN+/-and MSTN-/- cell colonies with single or double allele deletion by single transfection. Sequencing results demonstrated that 92.18% of the mutations were short fragment deletions or insertions (≤10 bp). Prediction of amino acids sequences indicated that more than half of the mutations cause premature transla-tional-termination codon. MSTN+/+, MSTN+/-, and MSTN-/- cell colonies were used as nuclear donor for somatic cell nuclear transfer (SCNT), and developmental potential of SCNT embryos were measured by the blastocyst rate. The results revealed no significant difference in development competence among the three kinds of reconstructed embryos (14.29% vs. 19.64% vs. 16.13%), which provides the possibility of making myostatin knock out pigs in the future.