Human Disease-Associated Genetic Variation Impacts Large Intergenic Non-Coding RNA Expression
Recently it has become clear that only a small percentage (7%) of disease-associated single nucleotide polymorphisms (SNPs) are located in protein-coding regions, while the remaining 93% are located in gene regulatory regions or in intergenic regions. Thus, the understanding of how genetic variations control the expression of non-coding RNAs (in a tissue-dependent manner) has far-reaching implications. We tested the association of SNPs with expression levels (eQTLs) of large intergenic non-coding RNAs (lincRNAs), using genome-wide gene expression and genotype data from five different tissues. We identified 112 cis-regulated lincRNAs, of which 45% could be replicated in an independent dataset. We observed that 75% of the SNPs affecting lincRNA expression (lincRNA cis-eQTLs) were specific to lincRNA alone and did not affect the expression of neighboring protein-coding genes. We show that this specific genotype-lincRNA expression correlation is tissue-dependent and that many of these lincRNA cis-eQTL SNPs are also associated with complex traits and diseases. Large intergenic non-coding RNAs (lincRNAs) are the largest class of non-coding RNA molecules in the human genome. Many genome-wide association studies (GWAS) have mapped disease-associated genetic variants (SNPs) to, or in, the vicinity of such lincRNA regions. However, it is not clear how these SNPs can affect the disease. We tested whether SNPs were also associated with the lincRNA expression levels in five different human primary tissues. We observed that there is a strong genotype-lincRNA expression correlation that is tissue-dependent. Many of the observed lincRNA cis-eQTLs are disease- or trait-associated SNPs. Our results suggest that lincRNA-eQTLs represent a novel link between non-coding SNPs and the expression of protein-coding genes, which can be exploited to understand the process of gene-regulation through lincRNAs in more detail.