Nature chemical biologyOct 8, 2025

Accurate and efficient flipping of large sections of DNA across chromosomes

CRISPR Gene Editing Weekly Brief ↗PubMed ↗DOI ↗

Updated Jun 28, 2026

Abstract

Essence

A prime-editing inversion platform enabled efficient, precise large-scale and chromosomal-scale DNA inversions in mammalian cells.

Evidence

This genome engineering platform study in mammalian cells reports that PIEv3b achieved precise inversion efficiencies up to 61.7% for 1 Mb and 14.2% for 50 Mb segments, was 4-fold to 20-fold more efficient than twin prime editing with integrase across 100 kb to 30 Mb ranges, and converted human chromosomes by inverting 30-Mb and 100-Mb segments.

Caveat

These results come from a mammalian cell genome-editing system, so therapeutic utility and performance in living organisms were not shown.

Simplified

Chromosomal inversion is a key structural variation impacting cellular fitness and genomic integrity. Here we developed prime-editing-based inversion with enhanced performance (PIE) to efficiently induce large-scale inversions in mammalian cells. PIEv1 uses a prime-editing guide RNA (pegRNA) pair but yields one imprecise junction. PIEv2 and PIEv3 add a second pegRNA pair for precise inversion, with PIEv3b further enhancing coupling precise inversion through improved plasmid design. PIEv3b achieves inversion efficiencies up to 61.7% for 1 Mb and 14.2% for 50 Mb segments and shows 4-20-fold higher efficiency compared to twin prime editing with integrase, across ranges of 100 kb to 30 Mb. Additionally, PIEv3b outperforms nuclease-based approaches in both inversion efficiency and precision. Using PIE, we convert human chromosomes from metacentric to telocentric configurations by inverting 30-Mb and 100-Mb chromosomal segments. Our work represents a powerful tool for engineering chromosomal structural variations, with broad implications for medicine and biotechnology.