New killer CRISPR system is unlike any scientists have seen
In 2012, scientists at Lawrence Berkeley National Laboratory published a paper showing that CRISPR could be used for genome editing. It turned out to be wildly successful, and not just in bacteria — if you correctly program CRISPR-Cas9, you can deactivate or remove genes in plants, animals, and even humans.
Since then, researchers have used CRISPR-Cas9 to treat diseases, create healthier crops, and more. They’ve also discovered and utilized CRISPR proteins beyond Cas9, such as Cas13, which cuts single-stranded RNA molecules rather than double-stranded DNA molecules.
Now, researchers in the US and Germany have published two papers detailing a new CRISPR protein — Cas12a2 — which they say is more like a genetic Swiss Army Knife than a pair of scissors.
“With this new system … we’re seeing a structure and function unlike anything that’s been observed in CRISPR systems to date,” said researcher Ryan Jackson from Utah State University.
While other CRISPR systems bind to their target sequence, make their cut, and then stop, the researchers learned through a technique called “cryo-electron microscopy” that when Cas12a2 binds to its target, it seems to “activate,” transforming in shape.
Once activated, the protein can bind to any genetic material that comes near it, whether its single-stranded RNA, single-stranded DNA, or double-stranded DNA. Cas12a2 then starts shredding the material, making multiple cuts in indiscriminate locations.
Because the genetic material can belong to the bacteria itself, the result can be cellular death. Essentially, CRISPR causes the infected cell to self-destruct — rather than let it become a virus factory.
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