Scientists Develop Hyper Accurate Cas9 for CRISPR

Scientists from the University of California Berkeley continue to be ahead of the CRISPR game. Together with researchers at Massachusetts General Hospital and Harvard University, they have designed a more precise version of Cas9, the enzyme that cuts DNA. The result of their study is published in Nature.

The researchers identified a key region called REC3 in the Cas9 protein that governs how accurately CRISPR-Cas9 homes in on a target DNA sequence, and redesigned it with a hyper-accurate gene editor with the lowest level of off-target cutting to date.

"If you mutate certain amino acid residues in REC3, you can tweak the balance between Cas9 on-target activity and improved specificity; we were able to find the sweet spot where there is sufficient activity at the intended target but also a large reduction in off-target events," said Janice Chen, one of the authors of the study and a graduate student in the lab of Jennifer Doudna, who co-invented the CRISPR-Cas9 gene-editing tool.

The hyper-accurate Cas9 or HypaCas9 has shown to retain its on-target efficiency, but is slightly better at discriminating between on- and off-target sites in human cells.

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