Studies On The Effects Of MSTN And SCD5 On Fatty Acid Metabolism In Pig Cells

With the improvement of living standards,the juicy and tender pork with meat flavors is in high demand.Thus,how to increase IMF content without significantly increase the fat in the carcass has become the main task of researchers.The mass of IMF mainly depends on the numbers and volumes of the adipocyte cells in muscle.However,until today our knowledge on the regulation of fatty acid synthesis in animals is still very limited,and cannot provide a practicable method for pig breeding.Therefore,under the condition of ensuring a reasonable lean meat rate,the research on increasing IMF content is the direction of pig breeding in the future.However,at present,our understanding of the mechanism of pig IMF deposition is very limited,which cannot guide pig breeding.Therefore,it is necessary to investigate the molecular mechanism on the intramuscular fat deposition.Myostatin(MSTN),members of TGF-? superfamily,it has been found in many species and plays very important role in the development of skeletal muscle.It was found in many species that the deletions or mutations of MSTN gene can lead to significant increase of skeletal muscle.The mass of the skeletal muscle in the MSTN gene mice is about twice that of wild type mice.Stearoyl-COA desaturase 5(SCD5)is a key rate-limiting enzyme in the process of the formation of unsaturated fatty acids from saturated fatty acids,playing an important role in fatty acid metabolism.It was speculated that SCD5 may be a downstream molecule in the MSTN regulatory pathway.Therefore,study of the regulatory relationship between MSTN and SCD5 may provide new marker genes for improving pork quality.Gene overexpression and gene knockout are commonly used methods to study gene function.The method of construction of overexpression vector is very mature.RNA interference(RNAi)can specifically down regulate the target gene by inhibiting the translation of the mRNA.In this study,MSTN and SCD5 genes were cloned by PCR using porcine cell cDNA as the template,and the overexpression vectors p3×FLAG-CMV-MSTN and 3×FLAG-CMV-SCD5 were constructed.Three interference sites were selected for porcine MSTN and SCD5 gene,respectively,and their specific interference sequence and corresponding non-specific sequences were designed and synthesized.An effective interference sequence was selected by screening their efficiency of down-regulation of the genes with western blot.The results showed that there exists a connection,directly or indirectly between MSTN and SCD5 with the tendency of changing of SCD5 followed by the changing of MSTN in cells.Never the less,in either case the content of triglyceride in the cells has been significantly affected.The further rescue experiments have provided another line of evidence for revealing the regulatory relationship between MSTN and SCD5 genes.