Project description:We applied a massively parallel reporter assay (MPRA) in lymphoblastoid cells to functionally evaluate 49,256 allelic pairs, representing 30,893 genetic variants in high, local linkage disequilibrium for 744 independent cis-expression quantitative trait loci (eQTLs) assessed for colocalization across 114 traits.
Project description:Sequence variation in regulatory DNA alters gene expression and shapes genetically complex traits. However, the identification of individual, causal regulatory variants is challenging. Here, we used a massively parallel reporter assay to measure the cis-regulatory consequences of 5,832 natural DNA variants in the promoters of 2,503 genes in the yeast Saccharomyces cerevisiae. We identified 451 causal variants, which underlie genetic loci known to affect gene expression. Several promoters harbored multiple causal variants. In five promoters, pairs of variants showed non-additive, epistatic interactions. Causal variants were enriched at conserved nucleotides, tended to have low derived allele frequency, and were depleted from promoters of essential genes, consistent with the action of negative selection. Causal variants were enriched for alterations in transcription factor binding sites. Models integrating these features provided modest, but statistically significant, ability to predict causal variants. This work revealed a complex molecular basis for cis-acting regulatory variation.
Project description:Sequence variation in regulatory DNA alters gene expression and shapes genetically complex traits. However, the identification of individual, causal regulatory variants is challenging. Here, we used a massively parallel reporter assay to measure the cis-regulatory consequences of 5,832 natural DNA variants in the promoters of 2,503 genes in the yeast Saccharomyces cerevisiae. We identified 451 causal variants, which underlie genetic loci known to affect gene expression. Several promoters harbored multiple causal variants. In five promoters, pairs of variants showed non-additive, epistatic interactions. Causal variants were enriched at conserved nucleotides, tended to have low derived allele frequency, and were depleted from promoters of essential genes, consistent with the action of negative selection. Causal variants were enriched for alterations in transcription factor binding sites. Models integrating these features provided modest, but statistically significant, ability to predict causal variants. This work revealed a complex molecular basis for cis-acting regulatory variation.
Project description:Humans co-existed and interbred with other hominins which later became extinct. These archaic hominins are known to us only through fossil records and for two cases, genome sequences. Here we engineer Neanderthal and Denisovan sequences into thousands of artificial genes to reconstruct the pre-mRNA processing patterns of these extinct populations. Of the 5,224 alleles tested in this massively parallel splicing reporter assay (MaPSy), we report 969 exonic splicing mutations (ESMs) that correspond to differences in exon recognition between extant and extinct hominins. Using MaPSy splicing variants, predicted splicing variants, and splicing quantitative trait loci, we show that splice-disrupting variants experienced greater purifying selection in anatomically modern humans than in Neanderthals. Adaptively introgressed variants were enriched for moderate effect splicing variants, consistent with positive selection for alternative spliced alleles following introgression. As particularly compelling examples, we characterized a novel tissue-specific alternative splicing variant at the adaptively introgressed innate immunity gene TLR1, as well as a novel Neanderthal introgressed alternative splicing variant in the gene HSPG2 that encodes perlecan. We further identified potentially pathogenic splicing variants found only in Neanderthals and Denisovans in genes related to sperm maturation and immunity. Finally, we found splicing variants that may contribute to variation among modern humans in total bilirubin, balding, hemoglobin levels, and lung capacity. Our findings provide novel insights into natural selection acting on splicing in human evolution and demonstrate how functional assays can be used to identify candidate causal variants underlying differences in gene regulation and phenotype.
Project description:Large numbers of statistically significant associations between sentinel SNPs and case-control status have been replicated by genome-wide association studies (GWAS). Nevertheless, currently few underlying molecular mechanisms of complex disease are known. Our approach has been to investigate whether variation in binding of a transcription factor, the vitamin D receptor (VDR) whose activating ligand vitamin D has often been proposed as a modifiable factor in multiple disorders, could explain any of these associations. VDR modifies gene expression by binding DNA as a heterodimer with the Retinoid X receptor (RXR). We identified 43,332 genetic variants significantly associated with altered VDR binding affinity (VDR-BVs) using a high-resolution (ChIP-exo) genome-wide analysis of 27 HapMap lymphoblastoid cell lines (LCLs). The VDR-BVs are over-represented in well conserved consensus RXR:VDR binding motifs. However, most fell outside of recognisable RXR:VDR motifs, implying that genetic variation often affects RXR:VDR binding affinity only indirectly. Finally, we compared 341 VDR-BVs replicating by position in multiple individuals against background sets of variants lying within VDR-binding regions that had been matched in allele frequency and were independent with respect to linkage disequilibrium. In this stringent test, these replicated VDR-BVs were significantly (q < 0.1) and substantially (> 2-fold) enriched in GWAS intervals associated with autoimmune and other diseases, including inflammatory bowel disease, Crohn's disease and rheumatoid arthritis. Replicated VDR-BVs associated with these disorders could represent causal disease risk alleles whose effect is modifiable by vitamin D levels.
Project description:We present a joint single-cell atlas of gene expression and chromatin accessibility of the adult human retina. We integrate this atlas with a HiChIP enhancer connectome, expression quantitative trait loci (eQTL) data, and base-resolution deep learning models to predict noncoding variants with causal roles in eye disease.
Project description:To date, genome-wide association studies (GWAS) have revealed over 200 genetic risk loci associated with prostate cancer; yet, true disease-causing variants in gene regulatory regions remain elusive. Identification of causal variants and their targets from association signals relevant to prostate cancer is complicated by high linkage disequilibrium and limited availability of functional genomics data for specific tissue/cell types. Here, we integrated statistical fine-mapping and functional annotation from prostate-specific epigenomic profiles, high resolution 3D genome features, and quantitative trait loci data to distinguish causal variants from associations and identify target genes they regulate. Our fine-mapping analysis yielded 1,892 likely causal variants, and multiscale functional annotation linked them to 406 target genes. We prioritized rs10486567, located in an enhancer, as a genome-wide top-ranked SNP and predicted HOTTIP as its target. Deletion of the rs10486567-associated enhancer in prostate cancer cells decreased their capacity for invasive migration. HOTTIP overexpression in an enhancer-KO cell line rescued defective invasive migration. Furthermore, we found that rs10486567 regulates HOTTIP through allele-specific long- range chromatin interaction.
Project description:To date, genome-wide association studies (GWAS) have revealed over 200 genetic risk loci associated with prostate cancer; yet, true disease-causing variants in gene regulatory regions remain elusive. Identification of causal variants and their targets from association signals relevant to prostate cancer is complicated by high linkage disequilibrium and limited availability of functional genomics data for specific tissue/cell types. Here, we integrated statistical fine-mapping and functional annotation from prostate-specific epigenomic profiles, high resolution 3D genome features, and quantitative trait loci data to distinguish causal variants from associations and identify target genes they regulate. Our fine-mapping analysis yielded 1,892 likely causal variants, and multiscale functional annotation linked them to 406 target genes. We prioritized rs10486567, located in an enhancer, as a genome-wide top-ranked SNP and predicted HOTTIP as its target. Deletion of the rs10486567-associated enhancer in prostate cancer cells decreased their capacity for invasive migration. HOTTIP overexpression in an enhancer-KO cell line rescued defective invasive migration. Furthermore, we found that rs10486567 regulates HOTTIP through allele-specific long- range chromatin interaction.
Project description:To date, genome-wide association studies (GWAS) have revealed over 200 genetic risk loci associated with prostate cancer; yet, true disease-causing variants in gene regulatory regions remain elusive. Identification of causal variants and their targets from association signals relevant to prostate cancer is complicated by high linkage disequilibrium and limited availability of functional genomics data for specific tissue/cell types. Here, we integrated statistical fine-mapping and functional annotation from prostate-specific epigenomic profiles, high resolution 3D genome features, and quantitative trait loci data to distinguish causal variants from associations and identify target genes they regulate. Our fine-mapping analysis yielded 1,892 likely causal variants, and multiscale functional annotation linked them to 406 target genes. We prioritized rs10486567, located in an enhancer, as a genome-wide top-ranked SNP and predicted HOTTIP as its target. Deletion of the rs10486567-associated enhancer in prostate cancer cells decreased their capacity for invasive migration. HOTTIP overexpression in an enhancer-KO cell line rescued defective invasive migration. Furthermore, we found that rs10486567 regulates HOTTIP through allele-specific long- range chromatin interaction.