Project description:Background: Previous expression quantitative trait loci (eQTL) studies have identified thousands of genetic variants to be associated with gene expression at the mRNA level in the human liver. However, protein expression often correlates poorly with mRNA levels. Thus, protein quantitative trait loci (pQTL) study is required to identify genetics variants that regulate protein expression in human livers. Results: We conducted a genome-wide pQTL study in 287 normal human liver samples and identified 900 local-pQTL variants and 4,026 distant-pQTL variants. We further discovered 53 genome hotspots of pQTL variants. Transcriptional region mapping analysis showed that 1,133 pQTL variants are in transcriptional regulatory regions. Genomic region enrichment analysis of the identified pQTL variants revealed 804 potential regulatory interactions among 595 regulators (e.g. non-coding RNAs) and 394 proteins. Moreover, pQTL variants and trait-variant integration analysis uncovered several novel mechanisms underlying the relationships between protein expression and liver diseases, such as alcohol dependence. Notably, over 2,000 of the identified pQTL variants have not been reported in previous eQTL studies, suggesting extensive involvement of genetic polymorphisms in post-transcriptional regulation of protein expression in human livers. Conclusions: We have partially established protein expression regulation networks in human livers and generated a wealth of pQTL data that could serve as a valuable resource for the scientific community.
Project description:Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex disease of unknown etiology. Multiple studies point to disruptions in immune functioning in ME/CFS patients as well as specific genetic polymorphisms and alterations of the DNA methylome in lymphocytes. However, potential interactions between DNA methylation and genetic background in relation to ME/CFS have not been examined. In this study we explored this association by characterizing the epigenetic (~480 thousand CpG loci) and genetic (~4.3 million SNPs) variation between cohorts of ME/CFS patients and healthy controls. We found significant associations of DNA methylation states in T-lymphocytes at several CpG loci and regions with ME/CFS phenotype. These methylation anomalies are in close proximity to genes involved with immune function and cellular metabolism. Finally, we found significant correlations of genotypes with methylation modifications associated with ME/CFS. The findings from this study highlight the role of epigenetic and genetic interactions in complex diseases, and suggest several genetic and epigenetic elements potentially involved in the mechanisms of disease in ME/CFS.
Project description:To increase our understanding of the genes involved in flowering in citrus, we performed genome resequencing of an early flowering trifoliate orange mutant (Poncirus trifoliata L. Raf.) and its wild type. At the genome level, 3,932,628 single nucleotide polymorphisms (SNPs), 1,293,383 insertion/deletion polymorphisms (InDels), and 52,135 structural variations (SVs) were identified between the mutant and its wild type based on the citrus reference genome. Based on integrative analysis of resequencing and transcriptome analysis, 233,998 SNPs and 75,836 InDels were also identified between the mutant and its wild type at the transcriptional level. Also, 272 citrus homologous flowering-time transcripts containing genetic variation were also identified. GO and KEGG annotation revealed that the transcripts containing the mutant and the wild-type-specific InDel were involved in diverse biological processes and molecular function. Among these transcripts, there were 131 transcripts that were expressed differently in the two genotypes. When 268 selected InDels were tested on 32 genotypes of the three generas of Rutaceae for the genetic diversity assessment, these InDel-based markers showed high transferability. This work provides important information that will allow a better understanding of the citrus genome and that will be helpful for dissecting the genetic basis of important traits in citrus.
Project description:Genetic factors contribute to the development of ischemic stroke but their identity remains largely unknown. We tested the association with ischemic stroke of 210 single nucleotide polymorphisms (SNPs) associated with pathways functionally related to stroke. We observed an association between the rs7956957 SNP in LRP1 and next performed microarrays analysis in healthy individuals to investigate possible associations of LRP genotypes with the expression of other genes. Twelve blood samples were obtained from twelve different healthy subjects carrying different genotypes for the rs7956957 SNP of the LRP1 gene (GG, CG or CC).
Project description:Although genetic studies have identified many hundreds of loci associated with human traits and diseases, pinpointing the causal alleles remains difficult, particularly for non-coding variants. To address this challenge, we have enhanced the sensitivity and reproducibility of the massively parallel reporter assay (MPRA), adapting it to identify variants that directly modulate gene expression. We then applied it to over 29,000 single nucleotide and insertion/deletion polymorphisms from 3,965 cis-expression quantitative trait loci (eQTL). We demonstrate strong correlation between our MPRA approach and existing measures of regulatory function, and determine an approximate sensitivity of ~20% with a positive predictive value of 60-65% to detect an eQTL causal allele. We identify 842 variants showing differential expression between alleles, including 53 well-annotated variants associated with diseases and traits. Thus, we have created a resource of concrete leads for understanding the genetic basis of specific phenotypes and illustrate the promise of this kind of approach for comprehensively interrogating how non-coding polymorphism shapes human biology.