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Cytosine base editor 4 but not adenine base editor generates off-target mutations in mouse embryos.

ABSTRACT: Deaminase base editing has emerged as a tool to install or correct point mutations in the genomes of living cells in a wide range of organisms. However, the genome-wide off-target effects introduced by base editors in the mammalian genome have been examined in only one study. Here, we have investigated the fidelity of cytosine base editor 4 (BE4) and adenine base editors (ABE) in mouse embryos using unbiased whole-genome sequencing of a family-based trio cohort. The same sgRNA was used for BE4 and ABE. We demonstrate that BE4-edited mice carry an excess of single-nucleotide variants and deletions compared to ABE-edited mice and controls. Therefore, an optimization of cytosine base editors is required to improve its fidelity. While the remarkable fidelity of ABE has implications for a wide range of applications, the occurrence of rare aberrant C-to-T conversions at specific target sites needs to be addressed.

SUBMITTER: Lee HK

PROVIDER: S-EPMC6952419 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

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Cytosine base editor 4 but not adenine base editor generates off-target mutations in mouse embryos.

Lee Hye Kyung HK Smith Harold E HE Liu Chengyu C Willi Michaela M Hennighausen Lothar L

Communications biology 20200109 1

Deaminase base editing has emerged as a tool to install or correct point mutations in the genomes of living cells in a wide range of organisms. However, the genome-wide off-target effects introduced by base editors in the mammalian genome have been examined in only one study. Here, we have investigated the fidelity of cytosine base editor 4 (BE4) and adenine base editors (ABE) in mouse embryos using unbiased whole-genome sequencing of a family-based trio cohort. The same sgRNA was used for BE4 a ...[more]

PMID: 31925293

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