Deoxyribonuclease II (DNase II) levels in human vary depending on whether the individual has the DNASE2*H (high) allele or the DNASE2*L (low) allele. We examined the promoter activity of the 5′-flanking region of each of these alleles by transient transfection luciferase assay. DNASE2*H had 5-fold higher promoter activity than DNASE2*L in human hepatoma HepG2 cell. Comparison of the nucleotide sequences of the proximal promoter regions revealed a G to A transition at position −75; G and A residues were assigned to DNASE2*H and *L, respectively. Since no differences were found between the open reading frame sequences of these alleles, it is likely that the A−75G transition causes the allelic difference in the promoter activity of the gene, underlying the genetic polymorphism.
