Researchers design a Cas9 enzyme that cuts DNA only in the presence of particular drug.
There are various ways to turn CRISPR/Cas9’s gene-editing activity on and off in cells, such as exposing tailor-made Cas9 enzymes to a particular type of light or to specific drugs. Each technique developed so far has drawbacks—either being complicated or irreversible. So researchers took inspiration from the Cre-recombinase-based method to control gene expression and built a “user-friendly” protocol for reversibly activating and inactivating CRISPR.