Acis-regulatory element regulatesERAP2expression through autoimmune disease risk SNPs

Abstract

AbstractSingle nucleotide polymorphisms (SNP) near theERAP2gene are associated with autoimmune conditions such asCrohn’s disease, andbirdshot chorioretinopathy, as well as protection against lethal infections, including theBlack Death. Due to high linkage disequilibrium (LD), a great number of trait-associated SNPs are correlated withERAP2expression, however their functional mechanisms remain unidentified. We used genome editing and functional genomics to identify causal variants that remain obscured by LD. We demonstrate by reciprocal allelic replacement thatERAP2expression is directly controlled by the genotype of splice region SNP rs2248374. However, we demonstrate that autoimmune disease-risk SNPs located near the downstreamLNPEPgene promoter are independently associated withERAP2expression. Allele-specific conformation capture assays revealed long-range chromatin contacts between theLNPEPpromoter region and theERAP2promoter and showed that interactions were stronger in patients carrying the alleles that increase susceptibility to autoimmune diseases. Replacing the disease-associated SNPs in theLNPEPpromoter by reference sequences loweredERAP2expression. These findings show that clustered GWAS signals associated with diverse autoimmune conditions and lethal infections act in concert to control ERAP2 expression and that disease-associated variants can convert a gene promoter region into a potent enhancer of a distal gene.