Functional analysis of differences in transcriptional activity conferred by genetic variants in the 5′ flanking region of the IL12RB2 gene

Abstract
Interleukin 12 receptor β chain (IL12RB2) is a crucial regulatory factor involved in cell-mediated immune responses, and genetic variants of the gene encoding IL12RB2 are associated with susceptibility to various immune-related diseases. We previously demonstrated that haplotypes with single nucleotide polymorphisms (SNPs) in the 5′ flanking region of IL12RB2, including −1035A>G (rs3762315) and −1023A>G (rs3762316), affect the expression of IL12RB2, thereby altering susceptibility to leprosy and periodontal diseases. In the present study, we identified transcription factors associated with the haplotype-specific transcriptional activity of IL12RB2 in T cells and NK cells. The −1023G polymorphism was found to create a consensus binding site for the transcription factor activating protein (AP)-1, and enzyme-linked immunosorbent assay (ELISA)-based binding assays showed that these SNPs enhanced AP-1 binding to this region. In reporter assays, suppression of JunB expression using siRNA eliminated differences in the −1035G/−1023G and −1035A/−1023A regions containing IL12RB2 promoter activity in Jurkat T cells and NK3.3 cells. These results suggested that the −1035/−1023 polymorphisms created differential binding affinities for JunB that could lead to differential IL12RB2 expression. Moreover, the −1035G and −1035A alleles formed binding sites for GATA-3 and myocyte enhancer factor-2 (MEF-2), respectively. Our data indicated...

Source: Immunogenetics - November 9, 2015 Category: Genetics & Stem Cells Source Type: research