The classic CRISPR system cuts DNA. Other variants cleave RNA. But now in the toolbox of new biotechnologies may come a tool that targets proteins: a CRISPR-driven caspase, already dubbed Craspase. What remains constant is that all these tools are programmable, thanks to the guide molecule that recognizes the desired target and directs the scissors there for editing. They are not paper shredders, rather they act like scalpels.

Selectively eliminating proteins by combining CRISPR’s programmability powers with the caspase’s ability to cut proteins could be helpful for both basic and applied research. I asked a scientist friend, Pino Macino, what he would do with it.

Here is his answer: ‘I would put it with an optogenetic promoter [i.e. activated by a light pulse] to kill specific cells in an organoid or an animal embryo. It would be very useful for quite a few developmental studies’. But this is just one possible example.

Here you can find the paper published this summer in Science by the Cornell University group led by Ailong Ke (warning: it is rather complicated) . According to the authors, since craspases do not touch DNA, “they could be a safe alternative to Cas nucleases and have the potential to be used in therapeutic applications in the future”.