Experiment / E7AIKCNVS3' UTR / RNA Stability MPRA (MPRAu)

HEK293T episomal MPRA of downstream-of-PAS 8-bp sequence variants

Slight Variations in the Sequence Downstream of the Polyadenylation Signal Significantly Increase Transgene Expression in HEK293T and CHO Cells

Nine barcoded plasmid libraries tested randomized sequence variants in overlapping 8-bp windows located +17 to +56 bp downstream of the polyadenylation signal of an eGFP reporter in transiently transfected HEK293T cells. The processed table aggregates the authors' barcode-level measurements to one ROI/mutation row per library and preserves the associated barcode count and activity dispersion.

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

Episomal pTTC-hPGK-eGFP plasmid libraries placed randomized 18-bp barcodes in the reporter 3' region and randomized 8-bp ROIs at nine overlapping positions downstream of the PAS. An equimolar pool of two wildtype reference constructs with specific 20-bp barcodes was spiked into each library at 1:100. HEK293T cells were harvested 48 h after transfection; mapping, plasmid-normalization, and cDNA-expression samples were sequenced as 151-nt single-end Illumina MiSeq reads and decoded with MPRAdecoder. Barcode RNA/DNA abundance was normalized to the wildtype reference, and ROI activity was averaged across associated barcodes. The paper additionally validated selected sequences with non-barcoded eGFP and NanoLuc constructs in HEK293T and CHO cells, but those validation assays are not part of this MPRA table.

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 · 26 definitions
library_id
Overlapping ROI window relative to the PAS, formatted as +start..+end bp.
window_start_bp_downstream_of_PAS
Start coordinate of the library window in bp downstream of the PAS.
window_end_bp_downstream_of_PAS
End coordinate of the library window in bp downstream of the PAS.
roi_sequence
Observed sequence of the region of interest in the source MPRAdecoder output.
roi_length_bp
Length in bp of the observed ROI sequence.
barcode_count
Number of source barcode rows associated with this ROI.
barcode_length_min_bp
Shortest observed barcode length among associated barcode rows.
barcode_length_max_bp
Longest observed barcode length among associated barcode rows.
barcodes_with_nonzero_expression
Associated barcode rows with a positive expression mean.
barcodes_with_zero_expression
Associated barcode rows with zero expression mean.
normalization_replicate_count
Number of normalization measurement columns in the source workbook.
expression_replicate_count
Number of expression measurement columns in the source workbook.
normalization_mean_across_barcodes
Arithmetic mean of the source per-barcode normalization means.
expression_mean_across_barcodes
Arithmetic mean of the source per-barcode expression means.
normalized_expression_mean_across_barcodes
Arithmetic mean of source normalized expression values before wildtype-reference scaling.
normalized_expression_sd_across_barcodes
Sample standard deviation of source normalized expression values across associated barcodes.
activity_ratio_source_column
Original source column used for the wildtype-reference-normalized activity ratio.
activity_ratio_to_wildtype_reference
Arithmetic mean of the source activity ratios across associated barcodes; 1 is the wildtype-reference level.
activity_ratio_median_across_barcodes
Median source activity ratio across associated barcodes.
activity_ratio_sd_across_barcodes
Sample standard deviation of source activity ratios across associated barcodes.
activity_ratio_min
Minimum source activity ratio among associated barcodes.
activity_ratio_max
Maximum source activity ratio among associated barcodes.
log2_activity_ratio
Log2 of the mutation-level activity ratio to the wildtype reference.
effect_category
Mutation-level effect call: increased_2x_or_more, decreased_2x_or_more, or within_2x.
qc_pass
Boolean indicating that the ROI group passed package QC and was retained.
source_file
Raw GEO workbook from which this ROI group was processed.

Quality control

The source spreadsheets are MPRAdecoder processed output, with barcode-ROI associations recovered from mapping samples and barcode expression normalized to plasmid abundance. Package QC retained 226,964 of 227,755 published ROI/mutation groups: groups were required to have finite values, a positive normalization mean, and at least one nonzero expression signal across the expression replicates; the 791 groups with zero total expression across both expression replicates (the groups counted as zero-expression in published Table 2) were excluded. Groups with some zero-expression barcode rows were retained when other associated barcodes provided expression. Source-reported ROI length variants of 7 or 9 bp were retained because they are present in the authors' processed output and are flagged in the table.

Curation notes

This is one MPRA screen comprising nine overlapping synthetic libraries, not nine independent biological conditions. The raw workbooks contain one row per barcode (406,137 rows); the processed table uses one row per unique ROI/mutation (226,964 retained rows) because the paper's reported activity and Table 2 summaries are ROI-level averages across associated barcodes. The nominal design is 8-bp ROI and 18-bp barcode, but the source output includes 7/9-bp ROI and 16-20-bp barcode observations, consistent with the decoder's allowed length tolerance; these observations were retained and their lengths are explicit. No genomic locus or reference assembly applies to the synthetic reporter library. HEK293T was resolved to Cellosaurus CVCL:0063. CHO and selected non-barcoded reporter validations are described in the paper but are not separate MPRA experiments.

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