Functional Genetic Variants Within The SIRT2 Gene Promoter In Type 2 Diabetes Mellitus

Objective: Our purpose is study the relationship between the genetic variants of SIRT2 gene promoter and the development of T2 DM by genetic and functional analysis of SIRT2 promoter in patients with T2 DM and healthy controls.Methods: We used large cohorts case control study,including T2 DM patients(n=365)and ethnic-matched controls(n=358).PCR was used to amplify SIRT2 gene promoter sequence with designed primers.PCR products were bi-directionally sequenced.The DNA sequences were then aligned and compared with the wide type SIRT2 gene promoter.Then functional analysis with dural-luciferase reporter assay.The variants of SIRT2 gene promoters were inserted into the pGL3-Basic vector.We transfected INS-1cells and HEK-293 cells with recombinant pGL3-Basic vector.After measuring luciferase,functional changes of SIRT2 gene promoters were compared and analyzed.Results: Total 18 DNA sequence vaxiants(DSVs)were identified,including 5 single-nucleotide polymorphisms(SNPs).We identified four novel heterozygous DSVs in four T2 DM patients.They are g.38900912G>T,g.38900561C>T,g.38900359C>T and g.38900237G>A.None of them existe in controls,three of which(g.38900912G>T,g.38900359C>T and g.38900237G>A)significantly increased the transcriptional activity of the SIRT2 gene promoter in cultured pancreatic beta cells(p<0.01).Seven novel heterozygous DSVs were only found in controls,and one heterozygous deletion DSV and five SNPs were found in both T2 DM patients and controls,which did not significantly affect SIRT2 gene promoter activity(p>0.05).Conclusion: Our findings suggested that the DSVs may increase SIRT2 gene promoter activity and SIRT2 levels,contributing to T2 DM development as a risk factor.