Catalog of 162 single nucleotide polymorphisms (SNPs) in a 4.7-kb region of the HLA-DP loci in southern Chinese ethnic groups

Abstract

HLA class-II proteins are cell-surface molecules that present antigens to T cells, and their expressional regulation is crucial to the immune reaction. Sequence variation at the regulatory region can directly affect the gene expression level. We cloned and sequenced a 4.7-kb region containing the regulatory region, exonl, and partial intron1 of both HLA-DPA1 and DPB1 genes in 25 variable sequences from southern Chinese ethnic groups and got a high-density map of 162 single nucleotide polymorphisms (SNPs): seven in 5′-flanking regions, four in 5′-untranslated regions, and four in the coding regions. By comparing these data with SNPs in dbSNP database in the NCBI, 145 SNPs (89.5%) were novel. In addition, eight genetic variations of insertion-deletion polymorphisms (INDELs) were discovered within the 4.7-kb region. These high-resolution maps can be used as resources of markers for association studies of complex diseases, assessment of individuals' predisposition to diseases, and tailoring of therapies, as well as research markers for population genetics and evolution.