miR-491 inhibits skeletal muscle differentiation through targeting myomaker.

The myogenesis of skeletal muscle has several stages, including satellite cell proliferation, differentiation, fusion and specific muscle formation. Recent studies have shown that myomaker, a muscle-specific transmembrane protein, was critical for myoblasts fusion. However, the regulatory mechanism of myomaker and its effects on myogenesis remain elusive. In this study, miR-491 was identified as a post-transcriptional regulator of myomaker, which binds specifically to its 3' untranslated region leading to its down-regulation. At the end of myotube differentiation, the expression levels of miR-491 increased drastically, while myomaker was significantly down-regulated, which indicated that miR-491 shut down the expression of myomaker. Functional studies showed that miR-491 overexpression suppressed muscle cell differentiation and adult muscle regeneration, while the inhibition of miR-491 promoted myotube differentiation. Taken together, our findings identified miR-491 as a novel negative regulator of myogenic differentiation through targeting myomaker.