Gene-editing Hack Yields Pinpoint Precision (Nature) [View all]

[HuckleB]

Disabled CRISPR enzyme allows efficient single-letter DNA changes.
http://www.nature.com/news/gene-editing-hack-yields-pinpoint-precision-1.19773

"A painstaking re-engineering of the CRISPR gene-editing system has given researchers the ability to alter individual DNA letters efficiently in a given gene. The advance boosts the success of such edits, and could boost scientists’ ability to model human diseases and develop treatments for them.

Researchers have been quick to embrace a gene-editing tool called CRISPR–Cas9, which lets them modify targeted genes with unprecedented ease. But although it is easy to use the tool to wipe out a gene’s function, it has been difficult to fix a ‘point mutation’ — caused by a change in a single DNA letter in a given gene — by correcting just the letter affected.

Those point mutations are important. “It turns out that the majority of disease-associated human genetic variants are point mutations,” says David Liu, a chemical biologist at Harvard University in Cambridge, Massachusetts. “But current genome methods correct point mutations much less efficiently and much less cleanly than we can disrupt a gene.”

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There are hundreds of other disease-associated mutations that could be corrected using a C to U switch, says Liu. But the team is now working to expand its reach to other point mutations, and to try the technique in animals. Liu hopes that his tricked-out enzymes will make it easier to create animal models that carry human mutations associated with disease. And eventually, after years of testing and refinement, the modified Cas9 could even be used to treat disease.

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Good news.