| Fad24(factor for adipocyte differentiation24) is reported to be a crucial gene regulating adipogenesis. However, several studies also showed that the expression of fad24is varied during myogenic differentiation and fad24knockout impair the skeletal muscle development in zebrafish, which indicate that fad24may also play a role in myogenesis, although the mechanism remains elusive. The aim of the current study is to systematically analyze the effect of fad24on proliferation and differentiation of mouse C2C12myoblasts. RNAi was employed to inhibit the endogenous expression of fad24in myoblasts, and its influences on proliferation, cell cycle progress, gene expression related to cell cycle and myogenesis, as well as cell morphology were examined. We confirmed that fad.24affects both proliferation and differentiation of myoblasts, and explored the possible mechanism. The major results of our study are as follows:1. Fad24is expressed in undifferentiated myoblasts, up-regulated upon myogenic induction and reached peak level at6h, and down-regulated afterwards. The dynamic expression pattern indicates fad24is possibly involved in the regulation of myoblast differentiation.2. In proliferating C2C12cells, fad24knockdown significantly inhibited the increase in cell number, Accordingly, the expression of CyclinD1, E, A and cyclin-dependent kinase CDK2and CDK4were down-regulated, whereas the expression of cyclin-dependent kinase inhibitor P21was up-regulated. Flow cytometric analysis also showed that fad24-knockdown myoblasts were arrest at G1phase of cell cycle. The results indicate that fad24may affect myoblast proliferation through regulation of cell cycle progress.3. Upon myogenic induction,fad24-knockdown C2C12cells showed lower expression of myoD and myf5, which impairs myogenesis and inhibits myotube formation. The data indicates that fad24may regulate the differentiation of myoblasts via affecting the expression of genes essential for myogenesis. |
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