Single-nucleotide Polymorphism (SNP) in β-Defensin 2 in a Japanese Population and an Effect of - 1029 SNP on Promoter Activity

Human β-defensin (hBD) 2 is an epithelial antimicrobial peptide. We studied single-nucleotide polymorphisms in the gene of hBD-2 in a Japanese population, and estimated the effect of a polymorphism in the promoter/enhancer region on the transcriptional activity. By sequencing the hBD-2 gene of 50 unrelated individuals, we detected one SNP in exon 2 and nine SNPs in the promoter/enhancer region. The SNP in the coding region at the + 1765 position is synonymous [CCC (Pre)→CCT (Pre)]. One SNP in the promoter region (-1029) is located at the consensus sequence for NF-IL6 binding. By luciferase reporter assay and electrophoretic mobility shift assay, the wild-type (G) of -1029 showed significantly lower transcriptional activity than did the variant-type (A). The SNP at position -1029 may influence the hBD-2 expression and cause genetic variations in susceptibility to infectious diseases.