CRISPR 'Kill' Switch Could Make Human Gene Editing Safer

A weapon that viruses use in their neverending war with bacteria could be used to turn off the world’s most powerful gene-editing tool. "It's just basically a single protein that we can make in the cell or deliver to the cell that will turn off Cas9, [and] stop it from binding and cutting DNA," said study author Joseph Bondy-Denomy, a microbiologist at the University of California, San Francisco. When a virus infiltrates a bacterial cell, the bacteria mobilize a sequence of DNA, called CRI