A chemical CRISPR off switch efficiently controls gene editing

Abstract

Chemical methods for regulating CRISPR activity hold great potential for spatiotemporal control of gene editing technologies. Here we report a small-molecule strategy to switch off CRISPR functionality. We develop clickable RNAs by modifying RNAs with an azido-containing functionality, which can be covalently conjugated in a second step with a complementary reaction partner, DBCO (dibenzocyclooctyne). We show that multimeric DBCO behaves quite differently than monoDBCO by imposing steric and topological constraints on RNAs. This generalizable strategy lays a solid foundation for developing clickable CRISPR off switches. We also show that this strategy works well for terminating CRISPR-Cas9-mediated genome editing in human cells.