Abstract
MicroRNAs (miRNAs) are evolutionarily conserved endogenous small non-coding RNAs that play critical roles in skeletal muscle development. In this study, we identified putative miRNAs that were differentially expressed in the longissimus dorsi muscle between fetus (75 days of pregnancy) and lamb (1 day of age). We detected 1208 miRNAs, 313 of which were differentially expressed. In particular, we found that miR-145-5p was differentially and highly expressed in lamb skeletal muscle. In addition, our results demonstrated that overexpression of miR-145-5p inhibited the differentiation and apoptosis of goat primary myoblasts (GPMs), whereas knockdown of miR-145-5p had the opposite effect. The coding domain sequence (CDS) of ubiquitin-specific peptidase 13 (USP13) was predicted and validated as a target of miR-145-5p. We also demonstrated that the influence as a key regulator of GPMs differentiation is primarily mediated by targeting and inhibiting USP13. Taken together, these results revealed a novel pathway in skeletal muscle development in which miR-145-5p targets CDS region of USP13 to regulate differentiation and apoptosis of GPMs.