Chang Fei, Fang Rui, Wang Meng, Zhao Xin, Chang Wen, Zhang Zaihu, Li Ning, Meng Qingyong
State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China.
China Agricultural University Pig Breeding Farm, Zhuo Zhou, Hebei, China.
Transgenic Res. 2017 Feb;26(1):25-36. doi: 10.1007/s11248-016-9985-x. Epub 2016 Oct 27.
Follistatin (FST), which was first found in the follicles of cattle and pigs, has been shown to be an essential regulator for muscle development. Mice that were genetically engineered to overexpress Fst specifically in muscle had at least twice the amount of skeletal muscle mass as controls; these findings are similar to earlier results obtained in myostatin-knockout mice. However, the role of follistatin in skeletal muscle development has yet to be clarified in livestock. Here, we describe transgenic Duroc pigs that exogenously express Fst specifically in muscle tissue. The transgenic pigs exhibited an increased proportion of skeletal muscle and a reduced proportion of body fat that were similar to those reported in myostatin-null cattle. The lean percentage of lean meat was significantly higher in the F1 generation of TG pigs (72.95 ± 1.0 %) than in WT pigs (69.18 ± 0.97 %) (N = 16, P < 0.05). Myofiber hypertrophy was also observed in the longissimus dorsi of transgenic pigs, possibly contributing to the increased skeletal muscle mass. Western blot analysis showed a significantly reduced level of Smad2 phosphorylation and an increased level of Akt phosphorylation in the skeletal muscle tissue of the transgenic pigs. Moreover, no cardiac muscle hypertrophy or reproductive abnormality was observed. These findings indicate that muscle-specific Fst overexpression in pigs enhances skeletal muscle growth, at least partly due to myofiber hypertrophy and providing a promising approach to increase muscle mass in pigs and other livestock.
卵泡抑素（FST）最初是在牛和猪的卵泡中发现的，已被证明是肌肉发育的重要调节因子。经过基因工程改造、在肌肉中特异性过表达Fst的小鼠，其骨骼肌质量至少是对照组的两倍；这些发现与早期在肌肉生长抑制素基因敲除小鼠中获得的结果相似。然而，卵泡抑素在牲畜骨骼肌发育中的作用尚未明确。在此，我们描述了在肌肉组织中特异性外源表达Fst的转基因杜洛克猪。转基因猪的骨骼肌比例增加，体脂比例降低，这与肌肉生长抑制素基因缺失牛的情况相似。转基因猪F1代的瘦肉率（72.95±1.0%）显著高于野生型猪（69.18±0.97%）（N = 16，P < 0.05）。在转基因猪的背最长肌中也观察到肌纤维肥大，这可能是骨骼肌质量增加的原因。蛋白质免疫印迹分析显示，转基因猪骨骼肌组织中Smad2磷酸化水平显著降低，Akt磷酸化水平升高。此外，未观察到心肌肥大或生殖异常。这些发现表明，猪中肌肉特异性Fst的过表达可促进骨骼肌生长，至少部分原因是肌纤维肥大，这为增加猪和其他牲畜的肌肉量提供了一种有前景的方法。
