Molecular characterization of GTP binding protein overexpressed in skeletal muscle (GEM) and its role in promoting adipogenesis in goat intramuscular preadipocytes

摘要

GTP binding protein overexpressed in skeletal muscle (GEM) is an important gene with many functions, such as regulating the rearrangement of cytoskeleton and the activity of voltage-dependent calcium channel, and GEM was regarded as a candidate gene for obesity. However, little investigation has been carried out to explore whether GEM affected the intramuscular fat (IMF) deposition of goat. To explore the role of GEM gene in goat, this gene was cloned and its tissue and temporal expression profile were detected. Effect of GEM on adipogenesis was examined by losing function of GEM in vitro. Thereafter, several lipid metabolism-related genes were examined, including CCAAT/enhancing-binding protein alpha (C/EBP alpha), CCAAT/enhancing-binding protein beta (C/EBP beta), lipoprotein lipase (LPL), preadipocyte factor 1 (Pref-1), peroxisome proliferator activated receptor gamma (PPAR gamma) and sterol regulatory element binding protein 1 (SREBP1). We found that the goat GEM gene consisted of 936 bp, which encoded a protein of 311 amino acids. The expression of GEM was higher in spleen, lung and large intestine and it appeared sharp in the interim stage of differentiation. Furthermore, GEM knockdown blocked adipogenesis and the expression of C/EBP alpha, C/EBP beta, LPL, PPAR gamma and SREBP1. These results indicated that GEM might promote lipid accumulation and adipogenesis.