The yield and quality of the skeletal muscle are important economic traits in livestock and poultry production. The musculoskeletal embryonic nuclear protein 1 (MUSTN1) gene has been shown to be associated with embryonic development, postnatal growth, bone and skeletal muscle regeneration; however, its function in the skeletal muscle development of chicken remains unclear. Therefore, in this study, we observed that the expression level of MUSTN1 increased in conjunction with the proliferation of chicken skeletal muscle satellite cells (SMSCs). Knockdown of MUSTN1 in SMSCs downregulated the expression of cell proliferation genes as Pax7, CDK-2 and differentiation-relate genes including MyoD, MyoG, MyHC and MyH1B, whereas it upregulates the expression of cell apoptosis gene (Caspase-3) (P < 0.05). However, the combined analysis of CCK-8 and EdU showed that the cell vitality and EdU-positive cells of the si-MUSTN1 transfected group were significantly lower than those of the negative siRNA group (P < 0.05). In addition, the knockdown of MUSTN1 significantly increased the cell population in the G0/G1 phase and significantly decreased the cell population in the G2/M phase (P < 0.05), whereas the overexpression of MUSTN1 showed opposite effect. Taken together, our findings indicates that MUSTN1 is an important molecular factor that is responsible for regulating muscle growth and development in chickens, particularly, proliferation and differentiation of SMSCs.

骨骼肌的产量和质量是畜禽生产中重要的经济性状。肌肉骨骼胚胎核蛋白 1 ( MUSTN1 ) 基因已被证明与胚胎发育、出生后生长、骨骼和骨骼肌再生有关；然而，其在鸡骨骼肌发育中的功能仍不清楚。因此，在本研究中，我们观察到MUSTN1的表达水平随着鸡骨骼肌卫星细胞（SMSCs）的增殖而增加。SMSCs中MUSTN1 的敲低下调了细胞增殖基因Pax7、CDK-2和包括MyoD在内的分化相关基因的表达, MyoG , MyHC和MyH1B , 而它上调细胞凋亡基因 ( Caspase-3 )的表达( P  < 0.05)。但CCK-8和EdU联合分析显示，si-MUSTN1转染组细胞活力和EdU阳性细胞显着低于siRNA阴性组（P  < 0.05）。此外，MUSTN1的敲低显着增加了 G0/G1 期的细胞数量，并显着减少了 G2/M 期的细胞数量（P  < 0.05），而MUSTN1的过表达则显示出相反的效果。综上所述，我们的研究结果表明MUSTN1是调控鸡肌肉生长发育的重要分子因子，尤其是SMSCs的增殖和分化。