Direct identification of hundreds of expression-modulating variants using a multiplexed reporter assay
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PROVIDER: PRJNA305000 | ENA |
REPOSITORIES: ENA
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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. The study consists of two separate MPRA experiments, a 78,958 oligo (79k study) and a 7,500 oligo library (7.5k). For each library we processed independent transfections into two lymphoblastoid cell lines; in total we completed 5 replicates of NA12878 and 3 replicates of NA19239. For the 79k library we also performed 5 replicate transfections into the hepatocarcinoma cell line HepG2. Raw data is provided as Illumina reads of the 20 bp barcode from the RNA extracted 24 hours post transfection as well as from the plasmid library used for transfection. We also provide oligo/barcode combinations from the âgfp vector in the form of a tab delimited file containing the raw sequence reads of the barcode (column 1) and genomic sequence (column 2). Processed count files are unnormalized counts for each oligo acquired by summing all barcode matches together for each replicate.
2016-06-01 | E-GEOD-75661 | biostudies-arrayexpress
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.
2016-06-01 | GSE75661 | GEO
Project description:Although studies have identified hundreds of loci associated with human traits and diseases, pinpointing causal alleles remains difficult, particularly for non-coding variants. To address this challenge, we adapted the massively parallel reporter assay (MPRA) to identify variants that directly modulate gene expression. We applied it to 32,373 variants from 3,642 cis-expression quantitative trait loci and control regions. Detection by MPRA was strongly correlated with measures of regulatory function. We demonstrate MPRA's capabilities for pinpointing causal alleles, using it to identify 842 variants showing differential expression between alleles, including 53 well-annotated variants associated with diseases and traits. We investigated one in detail, a risk allele for ankylosing spondylitis, and provide direct evidence of a non-coding variant that alters expression of the prostaglandin EP4 receptor. These results create a resource of concrete leads and illustrate the promise of this approach for comprehensively interrogating how non-coding polymorphism shapes human biology.
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Project description:Multiplexed Identification of Cytotoxic Cell assay (PAINTKiller assay)
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Project description:Here we describe a multiplex HDR reporter assay to concurrently measure the effects of hundreds of variants of BRCA1 for their role in DNA repair. Using this assay, we characterized the effects of 1,056 amino acid substitutions in the first 192 residues of BRCA1.
2018-06-29 | GSE116427 | GEO
Project description:Systematic Dissection of Sequence Elements Controlling σ70 Promoters Using a Genomically-Encoded Multiplexed Reporter Assay in E. coli
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Project description:Delineating functionally normal variants from functionally abnormal variants in tumor suppressor proteins is critical for cancer surveillance, prognosis, and treatment options. BRCA1 is a protein that has many variants of uncertain significance which are not yet classified as functionally normal or abnormal. In vitro functional assays can be used to identify the functional impact of a variant when the variant has not yet been categorized through clinical observation. Here we employ a homology-directed repair (HDR) reporter assay to evaluate over 300 missense and nonsense BRCA1 variants between amino acid residues 1280 and 1576, which encompasses the coiled-coil and serine cluster domains. Functionally abnormal variants tended to cluster in residues known to interact with PALB2, which is critical for homology-directed repair. Multiplexed results were confirmed by singleton assay and by ClinVar database variant interpretations. Comparison of multiplexed results to designated benign or likely benign or pathogenic or likely pathogenic variants in the ClinVar database yielded 100% specificity and 100% sensitivity of the multiplexed assay. Clinicians can reference the results of this functional assay for help in guiding cancer treatment and surveillance options. These results are the first to evaluate this domain of BRCA1 using a multiplexed approach and indicate the importance of this domain in the DNA repair process.
2023-10-13 | GSE237142 | GEO
Project description:Cell mediated cytotoxicity plays important roles in host immune defence and cancer immunosurveillance. Current technologies that study cell cytotoxicity are target cell centric and lack the capability to identify and isolate cytotoxic effector cells. We developed the Multiplexed Identification of Cytotoxic Cell assay (PAINTKiller), a novel flow cytometry compatible method for direct identification and sorting of cytotoxic effector cells. We demonstrate that this technique can accurately identify cytotoxic effector cells which can be isolated, expanded and retained its superior cytotoxic capability. This technique can also be easily combined with other flow cytometry complementary assays, cell sorting and sequencing. The results indicate that PAINTKiller assay will be a powerful tool to uncover the determinants of functional immune response and will be of significant interest for cell therapy manufacturing workflow.
2023-06-14 | GSE207508 | GEO
Project description:We employ a massively parallel reporter assay (MPRA) to measure the ex vivo activities of hundreds of K562 and HepG2 enhancers with known transcription factor motif instances. For seven selected motifs that correspond to known or predicted activators and repressors in the two cell types, we make directed modifications of the bases corresponding to these motifs and observe the changes in enhancer activity. Reporter mRNA-seq from HepG2 and K562 cells transfected with a ~55,000-plex MPRA plasmid pool containing 5,418 mutated human enhancer sequences, each linked to 10 distinct 10-nt tags. The reporter mRNA tags facilitate quantitation of their abundances. The same tags were also sequenced from the transfected MPRA plasmid pool to facilitate normalization to plasmid copy numbers.
2013-03-15 | E-GEOD-33367 | biostudies-arrayexpress
Project description:We employ a massively parallel reporter assay (MPRA) to measure the ex vivo activities of hundreds of K562 and HepG2 enhancers with known transcription factor motif instances. For seven selected motifs that correspond to known or predicted activators and repressors in the two cell types, we make directed modifications of the bases corresponding to these motifs and observe the changes in enhancer activity.
2013-03-15 | GSE33367 | GEO