Microscopy reveals mechanism behind new CRISPR tool

Microscopy reveals mechanism behind new CRISPR tool

New exploration from Cornell offers bits of knowledge into a line of CRISPR frameworks, which could prompt promising antiviral and tissue designing devices in creature and plants.

The exploration by Ailong Ke, the Robert J. Appel Professor of atomic science and hereditary qualities in the College of Arts and Sciences, and Stan J.J. Brouns at Delft University of Technology in the Netherlands, centers around a newfound CRISPR RNA-directed Caspase framework, also called Craspase.

CRISPR-Cas frameworks are RNA-directed nucleases in microbes that divide viral DNA or RNA focuses in exact areas to empower strong genome altering applications. Caspases are a group of proteases that control customized cell demise in creatures, including people. A new finding that caspase-like proteins could connect with CRISPR-Cas zapped mainstream researchers. Such CRISPR-directed caspases were given another name, Craspase.

“On one hand, this affiliation was absolutely surprising and focuses to novel methods of antiviral activity in microscopic organisms,” Ke said. “Then again, we could utilize a framework like this to foster numerous biotech and restorative applications, on the off chance that we see every one of the thingamajigs inside this hardware.”

Binding of target RNA displays the gating loop, exposes Site 1 active site, and triggers Cas11 hinge motion in Sb-gRAMP. Credit: Chunyi Hu and Ailong Ke

The specialists’ paper on the subject, “Craspase is a CRISPR RNA-directed, RNA-enacted protease,” was distributed Aug. 24 in Science. For this paper, analysts utilized cryo-electron microscopy previews of Craspase frameworks to make sense of how they separate to target RNA and enact protease compounds, which can separate protein.

“These snapshots lead to a high-definition molecular movie,” Ke said. “By watching it back and forth, we know precisely how Craspase identifies an RNA target, how this in turn activates the protease, how long the activity persists, and what eventually shuts the protease activity off. Ideas start to pour in, about how to draw power from this platform.”

Co-first author Chunyi Hu, a postdoctoral associate in Ke’s lab, said there was tremendous interest in the Craspase system. “Lots of competition. We and our Netherlands collaborators pooled our strength together and worked day and night to solve the puzzle,” Hu said. “The process holds exciting potential because the output of Craspase is protein rather than DNA degradation.”

“With other CRISPR technologies, one worries whether the enzymes we use to edit our DNA are safe enough, if there might be collateral damage or off-targeting,” Ke said. “With Craspase, we can achieve many of the same beneficial therapeutic outcomes without worrying about the safety of our genome.”

The work reported in the paper also helps researchers understand what Craspase does inside bacteria cells, Ke said. “Our collaborators’ work showed that it’s like a master switch—the proteolytic cleavage triggers a cascade of events in the bacteria cells that likely kills them eventually,” Ke said. “We have a partial answer in this study. We’re still investigating.”

This recent research will also help scientists understand the similarities between programmed cell death in human cell pathways and the same process in bacterial cell pathways.

“We realize that the same set of proteases (caspases) are controlling the programmed cell death pathways in both kingdoms of life,” Ke said. “This observation revealed how deep-rooted this pathway is.”

Besides probing deeper into the functional side of this process, Ke said, and the team will move into the application side, which could include tissue engineering in animals and agricultural engineering. “I hope more investigators will appreciate the potential of this system and join in,” Ke said. “We all think about CRISPR-guided nuclease as a tool to cure genetic diseases, but CRISPR-guided proteases could have impacts for biology in a much broader way.”


More information: Chunyi Hu et al, Craspase is a CRISPR RNA-guided, RNA-activated protease, Science (2022). DOI: 10.1126/science.add5064

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