Cis-acting effect of the IL1B C−31T polymorphism on IL-1β mRNA expression

Since the effect of IL1B polymorphisms on IL-1β production is still controversial, we selected two polymorphisms to test their cis-acting effect on IL-1β mRNA expression by means of the allele-specific transcript quantification and the haplotype analysis. As for the C−31T polymorphism, we found that expression of the −31T allele was 2.2 times of the −31C allele. This higher transcription efficiency may correspond to the fact that C−31T is located in a TATA box. The other polymorphism, C+3954T, did not alter the levels of transcription. The use of the allele-specific transcript quantification enables us to exclude trans-acting effects of polymorphisms on the gene expression and contributes to understanding the roles of the IL1B polymorphisms in susceptibility to multifactorial diseases.