Allele-specific binding of the ubiquitous transcription factor OCT-1 to the functional single nucleotide polymorphism (SNP) sites in the tumor necrosis factor-alpha gene (TNFA) promoter

The tumor necrosis factor-alpha gene (TNFA) is characterized by several single nucleotide polymorphisms (SNPs) in its promoter region. Interestingly, some of these SNPs appear to influence TNFA expression and susceptibility to various human diseases, but the molecular mechanisms by which such possibly functional SNPs modulate TNFA expression are poorly understood. In this study, we show allele-specific binding of the ubiquitous transcription factor OCT-1 to the SNP sites at positions -863 and -857 in the promoter, which appear to affect TNFA expression: the protein was associated with variant allele possessing either -863A or -857T, but rarely with the common allele (-863C and -857C). The evidence presented here, therefore, suggests the possibility that OCT-1 could contribute to the modulation of TNFA expression by means of its allele-specific binding manner.