RNA-binding motif protein 24 regulates myogenin expression and promotes myogenic differentiation.

The formation of muscle fibers involves sequential expression of many proteins that regulate key steps during myoblast-to-myotube transition. Myogenin is a major player in the initiation and maintenance of myogenic differentiation in a mouse myoblast cell line, C2C12. RNA-binding proteins bind to specific target RNA sequences and regulate gene expression in a post-transcriptional manner. This study demonstrates that RNA-binding motif protein 24 (Rbm24) interacts with the 3'-untranslated region of myogenin mRNA and affects its half-life in C2C12 myogenesis. Knockdown of Rbm24 expression by RNA interference significantly decreased myogenin expression associated with the inhibition of myogenesis. In contrast, the overexpression of Rbm24 by stable transfection of a plasmid increased myogenin expression and had a positive effect on myogenic differentiation. Ectopic expression of myogenin was also able to restore myogenic differentiation in Rbm24-knockdown cells. Together, our results suggest that Rbm24 binds to myogenin mRNA and regulates its stability in C2C12 cells. Rbm24 plays a crucial role in myogenic differentiation at least in part through a myogenin-dependent post-transcriptional regulatory pathway.