Rewriting regulatory DNA to dissect and reprogram gene expression

Cell. 2025 Jun 12;188(12):3349-3366.e23. doi: 10.1016/j.cell.2025.03.034. Epub 2025 Apr 16.

Abstract

Regulatory DNA provides a platform for transcription factor binding to encode cell-type-specific patterns of gene expression. However, the effects and programmability of regulatory DNA sequences remain difficult to map or predict. Here, we develop variant effects from flow-sorting experiments with CRISPR targeting screens (Variant-EFFECTS) to introduce hundreds of designed edits to endogenous regulatory DNA and quantify their effects on gene expression. We systematically dissect and reprogram 3 regulatory elements for 2 genes in 2 cell types. These data reveal endogenous binding sites with effects specific to genomic context, transcription factor motifs with cell-type-specific activities, and limitations of computational models for predicting the effect sizes of variants. We identify small edits that can tune gene expression over a large dynamic range, suggesting new possibilities for prime-editing-based therapeutics targeting regulatory DNA. Variant-EFFECTS provides a generalizable tool to dissect regulatory DNA and to identify genome editing reagents that tune gene expression in an endogenous context.

Keywords: CRISPR; RNA FlowFISH; enhancers; gene regulation; high-throughput screening; non-coding variants; predictive models; prime editing; sequence design; transcription factors.

MeSH terms

  • Animals
  • Binding Sites
  • CRISPR-Cas Systems
  • Clustered Regularly Interspaced Short Palindromic Repeats
  • DNA* / genetics
  • DNA* / metabolism
  • Gene Editing* / methods
  • Gene Expression Regulation*
  • HEK293 Cells
  • Humans
  • Mice
  • Regulatory Sequences, Nucleic Acid* / genetics
  • Transcription Factors / metabolism

Substances

  • DNA
  • Transcription Factors