The virtual element in proximal promoter of porcine myostatin is regulated by myocyte enhancer factor 2C.

Myostatin (myostatin) is a member of the transforming growth factor-β superfamily. In this study, we investigated the transcriptional regulation of porcine myostatin expression in C2C12 cells. Sequence analysis of 2kb of the porcine myostatin gene upstream region revealed that it contains 16 E-box motifs. Using a serial deletion strategy, we identified a vital enhancer region between nucleotides -218 and -137 in promoter region of porcine myostatin. Gel-shift assay and deletion analysis result showed F1 site, from nucleotides -206 to -189, was the key element to produce the promoter/nucleus extract complex, which directly interact with transcriptional factor MEF2C. Overexpression of MEF2C increased myostatin promoter activity in dose dependent manner; and whereas introducing of small interfering RNA to MEF2C produced the opposite effect in both myoblasts and myotubes. When endogenous MEF2C was knocked down, the complex of protein/F1 was attenuated, and myostatin mRNA and protein level was also decreased. Thus, we propose that MEF2C could modulate and restrain myogenesis by myostatin activation and myostatin-dependent gene processing in porcine.