Swine PPAR-γ2 expression upregulated in skeletal muscle of transgenic mice via the swine Myozenin-1 gene promoter

Transgenic Res. 2015 Jun;24(3):409-20. doi: 10.1007/s11248-014-9849-1. Epub 2014 Nov 25.

Abstract

Myozenin-1 (Myoz1) gene-encoded calsarcin-2 protein was expressed exclusively in fast-twitch muscles. Peroxisome proliferator-activated receptor γ2 (PPAR-γ2) is a key regulator of adipocyte differentiation, fatty acid uptake and storage in mammals. In this study, transgenic (TG) mice were generated by injecting linearized DNA that contained mouse creatine kinase M-type enhancer, Myoz1 core promoter, swine PPAR-γ2 (sPPAR-γ2) and SV40 polyadenylation sequences into pronuclei of fertilized FVB/NJ mouse embryos using microinjection technology. Then, the TG mice were used to identify whether swine Myoz1 (sMyoz1) promoter could upregulate sPPAR-γ2 expression in skeletal muscle in a TG mouse model. The results showed that the sMyoz1 promoter indeed upregulated sPPAR-γ2 expression on both the RNA and protein levels. The target genes of PPAR-γ in fat formation pathways, such as fatty acid-binding protein 4 (FABP4) and lipoprotein lipase (LPL), were also overexpressed on the RNA level. Meanwhile, the level of skeletal muscle triacylglycerol in TG mice was increased (P < 0.05), and the result of Oil Red-O staining in the skeletal muscle sections also showed that the number of lipid droplets was significantly increased in TG mice compared to wild-type mice, which might improve the intramuscular fat (IMF) content. For pork, the quality was mostly influenced by the IMF; the identification of swine muscle-specific promoter, sMyoz1, could further serve to develop transgenic pigs with higher intramuscular fat contents and improve pork quality.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipocytes / physiology
  • Adipose Tissue / physiology
  • Animals
  • Female
  • Gene Expression Regulation
  • Male
  • Mice, Transgenic*
  • Muscle Proteins / genetics*
  • Muscle, Skeletal / physiology*
  • PPAR gamma / genetics*
  • Promoter Regions, Genetic
  • Sus scrofa / genetics
  • Triglycerides / metabolism
  • Up-Regulation

Substances

  • Muscle Proteins
  • PPAR gamma
  • Triglycerides