New killer CRISPR system is unlike any scientists have seen
It could lead to new cancer treatments, better diagnostics tests, and more.
By Kristin Houser

Researchers Chase Beisel and Oleg Dmytrenko. Credit: The Würzburg Helmholtz Institute for RNA-based Infection Research
This article is an installment of Future Explored, a weekly guide to world-changing technology. You can get stories like this one straight to your inbox every Thursday morning by subscribing here.

A unique CRISPR system that destroys infected cells is unlike anything scientists have ever seen before — and it could revolutionize how we use the powerful gene editing technology in the future.


CRISPR 101: While bacteria can infect humans, they can also be infected — a virus can inject its DNA in a bacterial cell and then use the cell like a virus factory, creating more and more copies of itself inside the cell until it bursts.

Just like we have an immune system to protect us against infections, some bacteria have a defense system called CRISPR.

CRISPR lets bacteria collect short DNA sequences from viruses it has seen before. Once it has a new DNA sequence, the CRISPR system creates CRISPR-associated (Cas) proteins, which contain copies of the sequence written in RNA.

Think Covid and then the vaccine, gain of function… this was from 2012 see article below..l



There are several different Cas proteins, but the one we know the most about is Cas9. Once created, it will float around a cell, waiting for its target to try to infect the bacteria again.

If that happens, the RNA sequence in the Cas9 protein will bind to the matching sequence in the viral DNA and cut through both sides of its double helix. The sliced-up viral DNA can then be destroyed by other proteins in the bacteria — stopping the infection.

“It’s a phenomenon that elicits audible gasps from fellow scientists.”

RYAN JACKSON
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.

What’s new? 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.

“It’s a change in structure that’s extraordinary to observe — a phenomenon that elicits audible gasps from fellow scientists,” said Jackson.


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.

“It’s poor for that particular cell, but it protects the whole colony of bacteria so that virus doesn’t spread through it,” said Jackson

[link to www.freethink.com (secure)]