Experiment / E0B3I2QHVEpisomal Plasmid MPRA

K562 allele-specific episomal MPRA

A screen of 1,049 schizophrenia and 30 Alzheimer’s-associated variants for regulatory potential

The study transfected one synthetic variant library into K-562 chronic myelogenous leukemia cells in three independent transfections. Each tested allele was represented by five uniquely barcoded oligonucleotide constructs in a pMPRA1 plasmid reporter, and DNA/RNA barcode sequencing was used to test differential allelic activity.

Processed tables are specific to each experiment. Column names, units, measurements, and table structure are not standardized across the database. Check this experiment’s column definitions and quality-control notes before comparing or combining data.

Perturbation & assay details

Basal / Untreated (plasmid transfection only)

A 95-bp variant-centered synthetic oligonucleotide was cloned into pMPRA1, with a CMV minimal promoter driving GFP and a unique barcode downstream of the reporter. Three independent K562 transfections were assayed by 50-bp single-end Illumina MiSeq sequencing of DNA and RNA barcode libraries; allele comparisons used total-count normalization and the paired mixed-model mpralm method.

Processed data

50 rows per page. Click a cell to inspect its full value.

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Filters apply to this table only. The CSV download contains the complete processed table; filtered rows are available through the API.

Column dictionary · 22 definitions
variant_id
dbSNP rs identifier for the assayed variant.
chromosome
Chromosome label from the source table.
position_hg19
1-based source SNP coordinate; the paper labels assayed SNP locations as hg19.
disease
Source disease group: SCZ (schizophrenia) or ALZ (Alzheimer’s disease).
assayed_alleles
Alleles represented in the sequence supplement, separated by |; these are not labeled as reference or risk alleles.
allele_count
Number of distinct allele constructs represented in the sequence supplement.
oligo_construct_count
Number of sequence-supplement constructs for this variant across all assayed alleles; normally five constructs per allele.
barcodes_per_allele
Designed barcode-indexed technical replicates per allele (5).
tested_region_length_bp
Length of the variant-centered sequence in the sequence supplement; most are 95 bp and rs159961 is 68 bp.
analysis_cell_line
Cell line represented by this experiment table (K562).
f_pvalue
Published raw F-test p-value for differential activity between alleles; it is not an effect-size estimate.
fdr
Published multiple-testing-adjusted F-test p-value/FDR for differential allelic activity.
significant_allelic_activity_fdr_lt_0_05
TRUE when the published FDR is < 0.05; indicates a significant allelic activity difference but not its direction.
max_cv_dna_ge5_A
Maximum CV of RNA/DNA ratios for the A allele after excluding barcodes with fewer than 5 DNA reads; blank means unavailable.
max_cv_dna_ge5_C
Maximum CV of RNA/DNA ratios for the C allele after excluding barcodes with fewer than 5 DNA reads; blank means unavailable.
max_cv_dna_ge5_G
Maximum CV of RNA/DNA ratios for the G allele after excluding barcodes with fewer than 5 DNA reads; blank means unavailable.
max_cv_dna_ge5_T
Maximum CV of RNA/DNA ratios for the T allele after excluding barcodes with fewer than 5 DNA reads; blank means unavailable.
max_cv_dna_ge10_A
Maximum CV of RNA/DNA ratios for the A allele after excluding barcodes with fewer than 10 DNA reads; blank means unavailable.
max_cv_dna_ge10_C
Maximum CV of RNA/DNA ratios for the C allele after excluding barcodes with fewer than 10 DNA reads; blank means unavailable.
max_cv_dna_ge10_G
Maximum CV of RNA/DNA ratios for the G allele after excluding barcodes with fewer than 10 DNA reads; blank means unavailable.
max_cv_dna_ge10_T
Maximum CV of RNA/DNA ratios for the T allele after excluding barcodes with fewer than 10 DNA reads; blank means unavailable.
qc_pass
TRUE for a row retained after the source successful-assay/statistical-result QC filter.

Quality control

The paper normalized DNA and RNA libraries by total counts, summarized each MPRA element by aggregated barcode counts, and calculated RNA/DNA-ratio coefficient of variation (CV) across the five allele barcodes. Barcodes with fewer than 5 or fewer than 10 DNA reads were omitted from the respective CV calculation, and SNPs with a CV above the 99th-percentile threshold were flagged. The paper retained successfully assayed SNPs for differential analysis rather than declaring a hard row-level CV exclusion; this package retains all 1,079 Table SS1 SNP rows with a numeric K562 F-test result and filters no K562 rows. Significant allelic activity is represented by the published adjusted F-test p-value/FDR < 0.05.

Curation notes

K-562 is resolved to Cellosaurus CVCL:0004 (the article gives ATCC CCL-243). Table SS1 does not report allele-specific MPRA effect sizes, reference/risk allele labels, or directions, so the processed table intentionally does not infer them. Rows with missing per-allele CV values are retained when the paper supplied a differential result because the authors used aggregated barcode counts for the statistical test. The four additional SNPs present in the sequence supplement but absent from Table SS1 were treated as unsuccessful assays and excluded from the processed table. The paper’s abstract spells the neuroblastoma line as SK-SY5Y in places, while the methods and cell-line accession identify the line used for this experiment as K562 only.

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