Identification And Function Analysis Of Skeletal Muscle Related MiRNA

microRNAs (miRNAs) contribute to the development and phenotypic variance of skeletal muscle in mammals and regulate gene expression by inhibiting translation or degrading mRNA. To understand the molecular mechanisms of porcine skeletal muscle phenotypes, we carried out miRNA profiling of skeletal muscle by Solexa sequencing of three different breeds, Landrace (lean-type), Tongcheng (obese-type) and Wuzhishan (mini-type) pigs. A total of 106 differential miRNAs were obtained when comparing Landrace vs Tongcheng pigs; 151 differential miRNAs were obtained when comparing Tongcheng vs Wuzhishan pigs; and 156 differential miRNAs were obtained when comparing Landrace vs Wuzhishan pigs. Interaction networks were constructed, according to the results of target prediction, by integrative analysis of up-regulated genes with down-regulated miRNAs or down-regulated genes with up-regulated miRNAs in each group, to decipher the molecular mechanisms underlying meat quality diversities with respect to differential miRNAs and genes.In addition, to decipher the molecular mechanisms of skeletal muscle development, the miRNA of skeletal muscles from DO and adult mice were identified by Solexa sequencing. A total of 422 (DO) and 336 (adult) known miRNAs were obtained. miRNAs with log2≥1 and p≤0.05 were considered to be differentially-expressed miRNAs between DO and adult mice. Candidate target genes were selected according the prediction results, combining with the transcriptome data from the skeletal muscle of these two stages. GO analysis suggested that the differential genes were mainly involved in the biological processes of cell cycle, adhesion, cell proliferation, regulation of muscle development, blood vessel development, extracellular structure organization, and the signaling pathway of Wnt signaling pathway, p53 signaling pathway, mTOR signaling pathway, and VEGF signaling pathway.Our findings provide useful information on the determinative role of miRNA in skeletal muscle development and meat quality among different pig breeds, and selection of molecular markers for meat quality, gowth and development.