Experiment / E2181MF4ADeep Mutational Scanning MPRA (DMS-MPRA)

PKLR promoter saturation-mutagenesis MPRA in K562, 48-hour harvest

Integration of multiple epigenomic marks improves prediction of variant impact in saturation mutagenesis reporter assay

A saturation-mutagenized 469-bp human PKLR promoter library was assayed in K562 cells with three independent plasmid transfections and a 48-hour harvest condition. Variant reporter activity was estimated from matched RNA and DNA tag counts.

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; 48 h post-transfection harvest

The episomal pGL4-derived promoter reporter carried the error-prone-PCR-mutagenized PKLR sequence and a random sequence tag in the reporter 3′ UTR. The library was transfected into K562 and collected after the 48-hour condition; matched DNA/RNA tag counts from three independent transfections were fit with log2(RNA) ~ log2(DNA) + N + offset to estimate each variant coefficient.

Processed data

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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 · 16 definitions
element_id
Paper Table 1 regulatory element name.
source_element_id
Element label in the authors' MPRA saturation-mutagenesis portal; PKLR-48h identifies the selected harvest condition.
variant_id
Stable package identifier combining element, GRCh38 coordinate, reference allele, and alternate allele.
chromosome
GRCh38 chromosome with chr prefix.
position_grch38
1-based GRCh38 position of the substituted nucleotide.
position_in_element
1-based position within the paper's reported target interval.
reference_allele
Reference/template nucleotide in the tested library.
alternate_allele
Single-nucleotide substitution introduced by saturation mutagenesis.
variant_class
Variant class; all retained rows are SNV.
barcode_count
Number of unique random tags associated with the variant.
dna_count
Source count of DNA sequences carrying the variant.
rna_count
Source count of RNA sequences carrying the variant.
log2_variant_effect
Portal-fitted regression coefficient estimating the log2 RNA/DNA reporter effect of the variant.
p_value
P-value for the fitted variant coefficient.
effect_direction
Direction derived from the coefficient sign: up, down, or no_change.
significant_p_lt_1e-5
Boolean indicating whether p_value is below the paper's nominal 1e-5 threshold.

Quality control

The source saturation-mutagenesis analysis used a minimum of 10 associated tags per variant. Package QC retained 1,376 of 1,404 candidate SNVs in the paper's Table 1 interval: GRCh38 SNVs with barcode_count >= 10, positive DNA/RNA counts, and finite coefficient and p-value were retained; 28 low-tag rows plus one-base deletions and out-of-interval records were excluded. The paper/CAGI analysis used p < 1e-5 as the nominal significance threshold, exposed as significant_p_lt_1e-5.

Curation notes

K562 is Cellosaurus CVCL:0004. The portal exposes PKLR-24h and PKLR-48h; the paper's PKLR condition is represented with the 48-hour source table, while the processed table is restricted to the 469-bp interval in paper Table 1.

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