MicroRNAs are a class of highly conserved similar to 20 nucleotides non-coding RNAs that post-transcriptionally regulate gene expression. Many miRNAs were studied in the development of skeletal muscle, such as miR-1, miR-206, and miR-133. In our previous study, miR-127-3p was found highly expressed in porcine fetal skeletal muscle, whereas the detailed functions of miR-127-3p in muscle development is still unclear. In this study, we detected that miR-127-3p also highly expressed in skeletal muscle, cardiac muscle of adult mice and proliferative C2C12 cell lines. Overexpression of miR-127-3p almost has no effects on differentiation of C2C12 cell lines. However, miR-127-3p significantly inhibited the cell proliferation of C2C12 cells. Moreover, we identified KMT5a as a target gene that was down-regulated in both mRNA and protein level when miR-127-3p mimics were introduced. Furthermore, KMT5a overexpression in miR-127-3p treated cells rescued the influence of miR-127-3p on C2C12 proliferation. In brief, our data reveals that miR-127-3p regulates the proliferation of myocytes through KMT5a. (C) 2018 Elsevier Inc. All rights reserved.