1Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education,Institute of Animal Nutrition,Sichuan Agricultural University,Chengdu,Sichuan 611130,China.
2College of Food Science,Sichuan Agricultural University,Yaan,Sichuan 625014,China.
Animal. 2017 Dec;11(12):2268-2274. doi: 10.1017/S1751731117001008. Epub 2017 May 11.
MicroRNAs (miRNAs) are a class of small non-coding RNAs that negatively regulate gene expression of target messenger RNAs (mRNAs) and miRNAs have been proven to play vital roles in skeletal muscle development. The miRNA-499-5p has been reported to be negatively related with the expression of Sox6, a critical transcription factor for the maintenance of fast-twitch skeletal muscle. In this study, we amplified a length of 2012-bp mRNA that contains a 1512-bp porcine Sox6 (pSox6) 3'UTR from skeletal muscle of a Duroc×Landrace×Yorkshire pig. By luciferase reporter assay we verified that pSox6 is a target of miR-499-5p. In extensor digitorum longus and Soleus muscles of pigs, the expression levels of miR-499-5p and pSox6 mRNA were also inversely correlated. Besides, overexpression of miR-499-5p in porcine satellite cells promoted the expression of MyHC I and MyHC IIa mRNA, along with a reduction of pSox6 mRNA. Taken together, these results indicate that miR-499-5p may facilitate the oxidative myofibers formation by downregulating pSox6 expression.
微小 RNA（miRNAs）是一类小的非编码 RNA，可负调控靶信使 RNA（mRNA）的基因表达，并且已证明 miRNAs 在骨骼肌发育中起着至关重要的作用。miRNA-499-5p 已被报道与 Sox6 的表达呈负相关，Sox6 是维持快肌的关键转录因子。在本研究中，我们从杜洛克×长白×约克夏猪的骨骼肌中扩增了一段包含 1512-bp 猪 Sox6（pSox6）3'UTR 的 2012-bp mRNA。通过荧光素酶报告基因实验，我们验证了 pSox6 是 miR-499-5p 的靶基因。在猪的趾长伸肌和比目鱼肌中，miR-499-5p 和 pSox6 mRNA 的表达水平也呈负相关。此外，miR-499-5p 在猪卫星细胞中的过表达促进了 MyHC I 和 MyHC IIa mRNA 的表达，同时降低了 pSox6 mRNA 的表达。综上所述，这些结果表明，miR-499-5p 可能通过下调 pSox6 的表达促进氧化型肌纤维的形成。
