Deng, ZhongliangChen, Jian-FuWang, Da-Zhi2012-01-032011Deng, Zhongliang, Jian-Fu Chen, and Da-Zhi Wang. 2011. Transgenic overexpression of miR-133a in skeletal muscle. BMC Musculoskeletal Disorders 12:115.1471-2474http://nrs.harvard.edu/urn-3:HUL.InstRepos:5978754Background: MicroRNAs (miRNAs) are a class of non-coding regulatory RNAs of ~22 nucleotides in length. miRNAs regulate gene expression post-transcriptionally, primarily by associating with the 3' untranslated region (UTR) of their regulatory target mRNAs. Recent work has begun to reveal roles for miRNAs in a wide range of biological processes, including cell proliferation, differentiation and apoptosis. Many miRNAs are expressed in cardiac and skeletal muscle, and dysregulated miRNA expression has been correlated with muscle-related disorders. We have previously reported that the expression of muscle-specific miR-1 and miR-133 is induced during skeletal muscle differentiation and miR-1 and miR-133 play central regulatory roles in myoblast proliferation and differentiation in vitro. Methods: In this study, we measured the expression of miRNAs in the skeletal muscle of mdx mice, an animal model for human muscular dystrophy. We also generated transgenic mice to overexpress miR-133a in skeletal muscle. Results: We examined the expression of miRNAs in the skeletal muscle of mdx mice. We found that the expression of muscle miRNAs, including miR-1a, miR-133a and miR-206, was up-regulated in the skeletal muscle of mdx mice. In order to further investigate the function of miR-133a in skeletal muscle in vivo, we have created several independent transgenic founder lines. Surprisingly, skeletal muscle development and function appear to be unaffected in miR-133a transgenic mice. Conclusions: Our results indicate that miR-133a is dispensable for the normal development and function of skeletal muscle.en-USmicroRNA-133askeletal muscletransgenicdifferentiationJournal Article2012-01-0310.1186/1471-2474-12-115