Megabase-scale human genome rearrangement with programmable bridge recombinases
Summary
Bridge recombinases are naturally occurring RNA-guided DNA recombinases that we previously demonstrated can programmably insert, excise, and invert DNA in vitro and in Escherichia coli. In this study, we report the discovery and engineering of the bridge recombinase ortholog ISCro4 for universal rearrangements of the human genome. We defined strategies for the optimal application of bridge systems, leveraging mechanistic insights to improve their targeting specificity. Through rational eng
Content
# Megabase-scale human genome rearrangement with programmable bridge recombinases
*Published: 2026 Mar 12*
Bridge recombinases are naturally occurring RNA-guided DNA recombinases that we
previously demonstrated can programmably insert, excise, and invert DNA in vitro
and in Escherichia coli. In this study, we report the discovery and engineering
of the bridge recombinase ortholog ISCro4 for universal rearrangements of the
human genome. We defined strategies for the optimal application of bridge
systems, leveraging mechanistic insights to improve their targeting specificity.
Through rational engineering of the ISCro4 bridge RNA and deep mutational
scanning of its recombinase, we achieved up to 20% insertion efficiency into the
human genome and genome-wide specificity as high as 82%. We further demonstrated
intrachromosomal inversion and excision, mobilizing up to 0.93 megabases of DNA.
Lastly, we provided proof of concept for plasmid-based excision of
disease-relevant gene regulatory regions or repeat expansions.
DOI: 10.1126/science.adz0276