Cloning And Bioinformatics Analysis Of SLA-DR Genes In Hunan Daweizi Pigs

Objective:To evaluate the potential of Daweizi pigs as xenotransplantation dnors from pigs to humans by analyzing the characteristics of SLA-DR genes in Hunan Daweizi pigs.Methods:SLA-DRA and SLA-DRB genes were amplified by RT-PCR, cloned into pUCm-T vectors, sequenced and analyzed through BLAST in NCBI and related software in ExPASY.Results:The SLA-DRA and SLA-DRB genes were 1177 and 909 nucleotides in length, which contain opening reading frame (ORF) and encode 252 and 266 amino acids respectively. Comparing the SLA-DRA and SLA-DRB genes with their counterpart sequences of human, the homologies of amino acid sequences were 82% and 73% respectively. The amino acids in SLA DR a chain of Daweizi pigs from position 124 to 136, which bind to human CD4, showed only two differences with HLA DRA:a Val→lle change at position 127 and a Thr→Ser change at position 136. The amino acids in SLA DRβchain of Daweizi pigs from position 134 to 148, which bind to human CD4, were identical with HLA-DRB. Further comparison with SLA sequences published in GenBank indicated that SLA-DRB gene found in Daweizi pigs has polymorphism while the homology of SLA-DRA gene is up to 100%. Phylogenetic tree of the SLA-DRB amino acid sequences indicates that Hunan Daweizi pig has close affinity with Banna pig and Wuzhishan pig. Conclusion:The cloned SLA-DRA and SLA-DRB in Hunan Daweizi pigs has high polymorphism with HLA-DRA and HLA-DRB in Human, indicates that Daweizi pigs have some advantages as xenotransplantation dnors from pigs to humans.