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Nat Biotechnol. 2018 Jan;36(1):95-102. doi: 10.1038/nbt.4021. Epub 2017 Nov 27.

Inhibition of 53BP1 favors homology-dependent DNA repair and increases CRISPR-Cas9 genome-editing efficiency.

Author information

1
The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
2
Department of Molecular Genetics, University of Toronto, Ontario, Canada.
3
Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
4
Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Langone Medical Center, New York, New York, USA.
5
The Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Ontario, Canada.

Abstract

Programmable nucleases, such as Cas9, are used for precise genome editing by homology-dependent repair (HDR). However, HDR efficiency is constrained by competition from other double-strand break (DSB) repair pathways, including non-homologous end-joining (NHEJ). We report the discovery of a genetically encoded inhibitor of 53BP1 that increases the efficiency of HDR-dependent genome editing in human and mouse cells. 53BP1 is a key regulator of DSB repair pathway choice in eukaryotic cells and functions to favor NHEJ over HDR by suppressing end resection, which is the rate-limiting step in the initiation of HDR. We screened an existing combinatorial library of engineered ubiquitin variants for inhibitors of 53BP1. Expression of one variant, named i53 (inhibitor of 53BP1), in human and mouse cells, blocked accumulation of 53BP1 at sites of DNA damage and improved gene targeting and chromosomal gene conversion with either double-stranded DNA or single-stranded oligonucleotide donors by up to 5.6-fold. Inhibition of 53BP1 is a robust method to increase efficiency of HDR-based precise genome editing.

PMID:
29176614
PMCID:
PMC5762392
DOI:
10.1038/nbt.4021
[Indexed for MEDLINE]
Free PMC Article

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