Background
Natural antisense RNAs are RNA molecules that are transcribed from the opposite strand of either protein-coding or non-protein coding genes and have the ability to regulate the expression of their sense gene or several related genes. However, the roles of natural antisense RNAs in the maintenance and myogenesis of muscle stem cells remain largely unexamined.
Conclusion
The results indicated that Foxk1-AS represses Foxk1, thereby rescuing Mef2c activity and promoting myogenic differentiation of C2C12 cells and regeneration of damaged muscle fibres. Video Abstract.
Methods
We analysed myoblast differentiation and regeneration by overexpression and knockdown of Foxk1-AS using lentivirus and adeno-associated virus infection in C2C12 cells and damaged muscle tissues. Muscle injury was induced by BaCl2 and the regeneration and repair of damaged muscle tissues was assessed by haematoxylin-eosin staining and quantitative real-time PCR. The expression of myogenic differentiation-related genes was verified via quantitative real-time PCR, Western blotting and immunofluorescence staining.
Results
We identified a novel natural antisense RNA, Foxk1-AS, which is transcribed from the opposite strand of Foxk1 DNA and completely incorporated in the 3' UTR of Foxk1. Foxk1-AS targets Foxk1 and functions as a regulator of myogenesis. Overexpression of Foxk1-AS strongly inhibited the expression of Foxk1 in C2C12 cells and in tibialis anterior muscle tissue and promoted myoblast differentiation and the regeneration of muscle fibres damaged by BaCl2. Furthermore, overexpression of Foxk1-AS promoted the expression of Mef2c, which is an important transcription factor in the control of muscle gene expression and is negatively regulated by Foxk1.