Background MicroRNAs(miRNAs)are highly conserved,short non-coding RNAs that regulate gene expression at the posttranscriptional level.Although many miRNAs are identified in muscles and muscle cells,their individual roles are still not fully understood.Result In the present study,we investigated a muscle highly-expressed miRNA,miR-127-3p,in C2C12 myoblasts and tissues of goats with different muscle phenotypes(Boer vs.Wushan black goats).Our results demonstrated that(1)miR-127-3p was extensively expressed in tissues of goats;(2)miR-127-3p was higher expressed in muscle,spleen,heart and skin in the muscular goats(Boer goats)than the control(the Wushan black goats).Then we further characterized the dynamical expression of miR-127-3p,MyoD,MyoG,Myf5,Mef2c and Myosin in the proliferating and differentiating C2C12 myoblasts at day of 0,1,3,5,and 7 in culture mediums.Especially,we found that miR-127-3p was significantly higher expressed in the proliferating than differentiating cells.Conclusion Our findings suggest that miR-127-3p probably play roles in the proliferation and differentiation of myoblasts,which further underlies regulation of muscle phenotype in goats.