Genetic Polymorphism Of Bovine MRVI1 Gene And Its Effect On Lipid Metabolism

The murine retrovirus integration site 1 homolog?MRVI1?gene is a tumor suppressor gene which have been found in mice.The gene has discovered several alternative splicing transcripts encoding different proteins.These transcripts have different translation initiation sites,including non-AUG?CUG?initiation sites^[1].The protein encoded by the MRVI1 gene is present in the endoplasmic reticulum and can be used as a substrate for c GMP-dependent kinase-1?PKG1?,and it can play a biological role by regulating IP3-induced calcium release.Studies have shown that MRV integration of the MRVI1 gene induces myeloid leukemia in mice by changing the expression of crucial genes for bone marrow cell growth and/or differentiation,so this gene can play an important role as an important gene for myeloid leukemia tumor suppression.The MRVI1 gene is a candidate gene related to beef quality traits selected on the basis of early transcriptomics analysis of this research group.This study intends to use this gene as the research object,through the screening and association analysis of SNPs of this gene,and at the cellular level to study its relationship with fat metabolism;to explore the effect and regulatory mechanism of MRVI1 gene on lipid metabolism,with a Provide new genetic resources for improving meat quality traits.In present study,the Chinese Simmental cattle were selected as the research object,and the meat quality and carcass traits of 135 Chinese Simmental cattle were determined.The genetic polymorphism of the MRVI1 gene was analyzed by direct sequencing.To further study the effect of MRVI1 gene on lipid metabolism and its regulatory mechanism,and explore whether the MRVI1 gene has molecular markers that can be used for assisted selection.The results showed that 8 SNP sites including g.41970426A>G,g.41970520T>C,g.41970609A>G,g.41970626G>A,g.41970714A>G were screened in the promoter sequence of the bovine MRVI1 gene.g.41971686G>A,g.41971818G>A,g.41972009A>C.Correlation analysis with carcass traits and meat quality traits of Chinese Simmental beef cattle showed that g.41970426A>G,g.41970520T>C,g.41970609A>G,g.41970714A>G and g.41971818G>A loci Significantly correlated with kidney fat and fat coverage?P<0.05?;g.41970626G>A site was significantly correlated with slaughter rate,kidney fat and carcass length?P<0.05?;g.41971686G>A site was correlated with fat coverage Significantly correlated with eye muscle area?P<0.05?;g.41970426A>G,g.41970520T>C,g.41970609A>G,g.41970626G>A,g.41970714A>G,g.41971818G>A and g.41972009T>G sites can be used as molecular markers of perianal fat traits?P<0.01?.The results showed that the SNPs which in the promoter region of the MRVI1 gene were related to the carcass and meat quality traits in Chinese Simmental cattle,which may have an important regulatory effect on lipid metabolism.On this basis,in order to further explore in this study,MRVI1 gene overexpression vector MRVI1-p BI-CMV3 and interference vector pb7sk-MRVI1-sh RNA were constructed to detect the effect of MRVI1 gene on the content of triglyceride,cholesterol and free fatty acid in bovine preadipocytes.The role of fatty acid synthesis.The results showed that the expression level of MRVI1 gene m RNA in bovine preadipocytes was significantly lower than that in the control group?P<0.05?,while the overexpression of MRVI1 gene in bovine preadipocytes was significantly higher than that in the control group?P<0.05?.The overexpression and silencing of MRVI1 gene significantly increased the content of triglyceride and cholesterol,and significantly reduced the content of free fatty acids.On this basis,in order to further explore the role and regulation mechanism of the MRVI1gene on lipid metabolism,our study constructed the MRVI1 gene overexpression vector MRVI1-p BI-CMV3 and the interference vector pb7SK-MRVI1-sh RNA.The effect of MRVI1gene on the synthesis of triglycerides,cholesterol and free fatty acids in the lipid metabolism pathway was detected in bovine preadipocytes.The changing of triglycerides,cholesterol and free fatty acids contents in cells reveals MRVI1 gene may be effect on the lipid metabolism pathway at the cellular level.The results showed that after interfering with the MRVI1 gene,the m RNA expression level of the MRVI1 gene in bovine preadipocytes was significantly lower than that in the control group?P<0.05?;however,after overexpressing the MRVI1 gene,it could be expressed in bovine preadipocytes.High-efficiency expression in the medium,significantly higher than the expression level of the control group?P<0.05?;MRVI1 gene overexpression and silencing in cells have a tendency to significantly increased the contents of triglycerides and cholesterol in the cells,and both significantly reduced free Fatty acid contents.In summary,g.41970426A>G,g.41970520T>C,g.41970609A>G,g.41970626G>A,g.41970714A>G,g.41971686G>A,present in the promoter region of the MRVI1 gene in bovine preadipocytes,g.41971818G>A,g.41972009A>C are significantly correlated with carcass and meat quality traits of Chinese Simmental beef cattle;meanwhile,MRVI1 gene regulates triglycerides,cholesterol and free fatty acids in bovine precursor fat cells still needs further exploration.The results of this study can provide a theoretical basis for the in-depth study of the related biological functions of the MRVI1 gene and its application in molecular assisted selection and breeding of beef cattle,as well as new genetic resources for molecular breeding of beef traits.