Effect of Actin Alpha Cardiac Muscle 1 on the Proliferation and Differentiation of Bovine Myoblasts and Preadipocytes

Actin Alpha Cardiac Muscle 1 (ACTC1) gene is a differentially expressed gene screened through the co-culture system of myoblasts-preadipocytes. In order to study the role of this gene in the process of proliferation and differentiation of bovine myoblasts and preadipocytes, the methods of the knockdown, overexpression, and ectopic expression of <i>ACTC1</i> were used in this study. After <i>ACTC1</i> knockdown in bovine myoblasts and inducing differentiation, the sizes and numbers of myotube formation were significantly reduced compared to the control group, and myogenic marker genes—MYOD1, MYOG, MYH3, MRF4, MYF5, CKM and MEF2A—were significantly decreased (<i>p</i> < 0.05, <i>p</i> < 0.01) at both the mRNA and protein levels of myoblasts at different differentiation stages (D0, D2, D4, D6 and D8). Conversely, <i>ACTC1</i> overexpression induced the inverse result. After ectopic expression of <i>ACTC1</i> in bovine preadipocytes and induced differentiation, the number and size of lipid droplets were significantly higher than those of the control group, and the expression of adipogenic marker genes—FABP4, SCD1, PPARγ and FASN—were significantly increased (<i>p</i> < 0.05, <i>p</i> < 0.01) at the mRNA and protein levels of preadipocytes at different differentiation stages. Flow cytometry results showed that both the knockdown and overexpression of <i>ACTC1</i> inhibited the normal cell cycle of myoblasts; however, ectopic expression of <i>ACTC1</i> in adipocytes induced no significant cell cycle changes. This study is the first to explore the role of <i>ACTC1</i> in bovine myogenesis and lipogenesis and demonstrates that <i>ACTC1</i> promotes the differentiation of bovine myoblasts and preadipocytes, affecting the proliferation of myoblasts.