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Base editing rewrites single DNA letters without cutting the double helix
From From Bacterial Defence to Medicine: The CRISPR Gene-Editing Revolution
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Breakthrough
Base editing rewrites single DNA letters without cutting the double helix
David Liu's lab combined Cas9 with an enzyme that converts one DNA base into another directly, correcting point mutations while avoiding the double-strand breaks that cause unwanted insertions and deletions.
Alexis Komor and David Liu's team fused a catalytically disabled Cas9 to a cytidine deaminase enzyme, creating a 'base editor' able to convert a C:G base pair directly into a T:A pair at a chosen site. Because the DNA backbone was never cut, the approach produced far fewer random insertions and deletions than standard Cas9. It gave researchers a second precision tool alongside the original cut-and-repair method, one better suited to correcting the many genetic diseases caused by single-letter mutations.
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