Study On Genetic Variants In UBXN1 Gene Promotor Region And Its Relationship With Water Holding Capacity In Pigs

The cytoskeleton of muscle maintains the morphology of muscle cells,it plays an important role in maintaining the WHC.The RhoA gene plays an important role in reorganizationing of actin cytoskeleton and the changing of morphology in cells.RhoA can also promotes the cytoskeletal contraction ang the protein binding levels,through RhoA-ROCK signal pathway.The UBX domain containing protein 1-like gene(UBXN1)is a potential candidate gene for pork quality.It promotes the degradation of protein which affects water holding capacity(WHC).The UBXN1 not only contains the UBA domain,it also has a UBX domain homology with ubiquitin.It can be combined with ubiquitin chains.the UBX domain of UBXN1 binding of p97 which involved in regulation of the ubiquitin proteasome pathway and the degradation of muscle fiber protein.Functional SNPs in the UBXN1 gene and RhoA gene promoter may lead to gene expression variations,and consequent WHC level in muscle.Firstly,we selected the high and low WHC groups(n = 16 for each group),Then we confirmed the positive correlation between UBXN1 gene expression and WHC.But the RhoA gene expression was negative correlation with WHC.Then the promoter region of UBXN1 and RhoA were comparatively scanned by direct sequencing DNA pools of high and low WHC groups(n = 16 for each group).A SNP of UBXN1 c.-379T>G was revealed for its reverse allele distribution in the two groups.The SNP was then genotyped in a population of 170 Duroc X Large White X Yorkshire(D X L X Y)pigs with the method of PCR-SSCP.The TT genotype exhibited higher WHC and UBXN1 mRNA level compared with GG genotype.Luciferase assay also revealed that TT genotype promoter had higher activity.The partial promoter sequences containing the mutation site c.-379T>G were applied to predict potential transcriptional factors using the BIMAS online tools.We found the mutation of this site resulted in the binding or disbanding of transcription factors.In conclusion,we identified a SNP in the UBXN1 gene promoter that potentially contributes to water holding capacity improvement.