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Enzyme prevents CRISPR making a clean cut
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An antiviral enzyme can cause accidental mutations during the repair of broken DNA strands.
The gene-editing tool CRISPR-Cas9 makes precise cuts in DNA strands. Repair of these breaks is required to complete the editing process, but can be scuppered by mutations, such as the unwanted insertion, deletion or replacement of base pairs – the building blocks of the DNA double helix. A team including researchers from ShanghaiTech University studied the role of APOBEC3, a family of antiviral enzymes produced in immune cells, in the repair of DNA breaks in E. coli samples. They find that APOBEC3 introduces mutations by turning a C-G base pair into a U-G base pair. In contrast, suppressing the activity of APOBEC3 reduced the number of mutations.
Preventing unintended mutations during DNA repair could help make gene editing tools more effective.
- Nature Structural & Molecular Biology 25, 45–52 (2018). doi: 10.1038/s41594-017-0004-6