The Francis Crick Institute
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Modulating mutational outcomes and improving precise gene editing at CRISPR-Cas9-induced breaks by chemical inhibition of end-joining pathways.

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journal contribution
posted on 2023-01-30, 11:21 authored by Joost Schimmel, Núria Muñoz-Subirana, Hanneke Kool, Robin van Schendel, Sven van der Vlies, Juliette A Kamp, Femke de Vrij, Steven A Kushner, Graeme CM Smith, Simon J Boulton, Marcel Tijsterman
Gene editing through repair of CRISPR-Cas9-induced chromosomal breaks offers a means to correct a wide range of genetic defects. Directing repair to produce desirable outcomes by modulating DNA repair pathways holds considerable promise to increase the efficiency of genome engineering. Here, we show that inhibition of non-homologous end joining (NHEJ) or polymerase theta-mediated end joining (TMEJ) can be exploited to alter the mutational outcomes of CRISPR-Cas9. We show robust inhibition of TMEJ activity at CRISPR-Cas9-induced double-strand breaks (DSBs) using ART558, a potent polymerase theta (Polϴ) inhibitor. Using targeted sequencing, we show that ART558 suppresses the formation of microhomology-driven deletions in favor of NHEJ-specific outcomes. Conversely, NHEJ deficiency triggers the formation of large kb-sized deletions, which we show are the products of mutagenic TMEJ. Finally, we show that combined chemical inhibition of TMEJ and NHEJ increases the efficiency of homology-driven repair (HDR)-mediated precise gene editing. Our work reports a robust strategy to improve the fidelity and safety of genome engineering.


Crick (Grant ID: CC2057, Grant title: Boulton CC2057) European Research Council (Grant ID: 742437 - TelMetab, Grant title: ERC 742437 - TelMetab)