AUTHOR=Zhao Zaoya , Yu Xiaozheng , Jia Jirong , Yang Guokun , Sun Caiyun , Li Wensheng 

TITLE=miR-181b-5p May Regulate Muscle Growth in Tilapia by Targeting Myostatin b

JOURNAL=Frontiers in Endocrinology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2019.00812

DOI=10.3389/fendo.2019.00812

ISSN=1664-2392

ABSTRACT=<p><bold>Background:</bold> Myostatin (Mstn), a member of the TGF-β superfamily, is a negative regulator of skeletal muscle mass in mammals. Precise regulation of Mstn expression is important for somite growth in fish. MicroRNA (miRNA), a type of small non-coding RNA, regulates gene expression at the post-transcriptional level and participates in various physiological functions. A growing amount of evidence has emphasized the importance of miRNA in the development of skeletal muscle.</p><p><bold>Aims:</bold> This study aims to study how miRNAs regulate <italic>myostatin b</italic> (<italic>mstnb</italic>) post-transcriptionally in tilapia.</p><p><bold>Methods/Results:</bold><italic>Mstnb</italic> 3′ UTR sequences were obtained, and the results of tissue distribution showed that <italic>mstnb</italic> was expressed in several tissues, including brain, white muscle, gut, and adipose tissue. A total of 1,992 miRNAs were predicted to target <italic>mstnb</italic> in tilapia using bioinformatics, and a dual-luciferase reporter experiment confirmed that miR-181a/b-5p, miR-30-3p, miR-200a, and miR-27a were the target miRNAs of <italic>mstnb</italic>. Mutagenesis of the miR-181b-5p binding sites of <italic>mstnb</italic> significantly increased the luciferase signal compared to the wild-type <italic>mstnb</italic>. In tilapia primary muscle cells, overexpression of miR-181b-5p led to the downregulation of MSTNb expression, and the inhibitory effect of MSTNb on the downstream genes was dismissed, while inhibition of miR-181b-5p could reverse these phenomena.</p><p><bold>Conclusion:</bold> Taken together, our results suggested that miR-181b-5p could promote the growth of skeletal muscle by decreasing the MSTNb protein level in tilapia.</p>