A systematic evaluation of the design and context dependencies of massively parallel reporter assays

Nat Methods. 2020 Nov;17(11):1083-1091. doi: 10.1038/s41592-020-0965-y. Epub 2020 Oct 12.

Abstract

Massively parallel reporter assays (MPRAs) functionally screen thousands of sequences for regulatory activity in parallel. To date, there are limited studies that systematically compare differences in MPRA design. Here, we screen a library of 2,440 candidate liver enhancers and controls for regulatory activity in HepG2 cells using nine different MPRA designs. We identify subtle but significant differences that correlate with epigenetic and sequence-level features, as well as differences in dynamic range and reproducibility. We also validate that enhancer activity is largely independent of orientation, at least for our library and designs. Finally, we assemble and test the same enhancers as 192-mers, 354-mers and 678-mers and observe sizable differences. This work provides a framework for the experimental design of high-throughput reporter assays, suggesting that the extended sequence context of tested elements and to a lesser degree the precise assay, influence MPRA results.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Enhancer Elements, Genetic
  • Gene Library*
  • Genes, Reporter*
  • Hep G2 Cells
  • High-Throughput Nucleotide Sequencing / methods*
  • Humans
  • Regulatory Sequences, Nucleic Acid*
  • Reproducibility of Results
  • Sequence Analysis, DNA / methods*
  • Transcription Factors / genetics

Substances

  • Transcription Factors