lnc-mg is a long non-coding RNA that promotes myogenesis [lncRNA]

Recent studies have indicated important roles for long noncoding RNAs (lncRNAs) as potential essential regulators of myogenesis and adult skeletal muscle regeneration. However, in vivo, the role and mechanism of lncRNAs in myogenic differentiation of adult skeletal muscle stem cells (MuSCs) and myogenesis are still largely unknown. Here, we identified a skeletal muscle specific-enriched lncRNA (myogenesis-associated lncRNA, short for lnc-mg). In vivo, skeletal muscle conditional knockout of lnc-mg resulted in muscle atrophy and the loss of muscular endurance during exercise. Alternatively, skeletal muscle-specific overexpression of lnc-mg promoted muscle hypertrophy in mice. In vitro analyses of primary skeletal muscle cells isolated from mice showed that expression of lnc-mg was increased gradually during myogenic differentiation and overexpressed lnc-mg improved cell differentiation. Mechanistically, lnc-mg promoted myogenesis, by functioning as a competing endogenous RNA (ceRNA) for miR-125b to control protein abundance of Igf2. These findings identify lnc-mg as a novel and important noncoding regulator for muscle cell differentiation and skeletal muscle development. In order to identify functional lncRNAs correlating with myogenesis, microarrays were performed to detect the lncRNAs expression profile in undifferentiated MuSCs (GM, growth media/GM) ) and differentiated MuSCs (DM, differentiation media/DM). Total RNAs was extracted from undifferentiated MuSCs (GM, growth media/GM) ) and differentiated MuSCs (DM, differentiation media/DM) by TRIzol Reagent (Life Technologies). Then the RNA quality was assessed by formaldehyde agarose gel electrophoresis, quantified spectrophotometrically and Agilent 2200 Bioanalyzer (Agilent, USA). Then labelled on Cy5 using ULS.