Effect of NR1D1 on the proliferation and differentiation of yak skeletal muscle satellite cells

The severe conditions at high altitudes, where yaks inhabit, contribute to delayed muscular growth and compromised tenderness of their muscle tissue. Myosatellite cells are responsible for the growth and regeneration of skeletal muscle after birth and have the potential to proliferate and differentiate, its development is closely related to meat quality, and the nuclear receptor gene <i>NR1D1</i> is involved in muscle formation and skeletal muscle regulation. Therefore, in order to understand the effect of <i>NR1D1</i> on muscle satellite cells, we identified the mRNA expression levels of marker genes specifically expressed in muscle satellite cells at different stages to determine the type of cells isolated. Eventually, we successfully constructed a primary cell line of yak muscle satellite cells. Then we constructed <i>NR1D1</i> overexpression vector and interference RNA, and introduced them into isolated yak skeletal muscle satellite cells. We performed qPCR, CCK8, and fluorescence-specific to detect the expression of genes or abundance of proteins as markers of cell proliferation and differentiation. Compared with those in the control group, the expression levels of proliferation marker genes <i>KI-67</i>, <i>CYCLIND1</i>, and <i>CYCLINA</i> were significantly inhibited after <i>NR1D1</i> overexpression, which was also supported by the CCK-8 test, whereas differentiation marker genes <i>MYOD</i>, <i>MYOG</i>, and <i>MYF5</i> were significantly inhibited. Fluorescence-specific staining showed that KI-67 protein abundance and the number of microfilaments both decreased, while the opposite trend was observed after <i>NR1D1</i> interference. In conclusion, we confirmed that <i>NR1D1</i> inhibited the proliferation and differentiation of yak skeletal muscle satellite cells, which provides a theoretical basis for further research on the effect of <i>NR1D1</i> on improving meat quality traits and meat production performance of yaks.