CRISPR-Cas systems, identified for their powerful gene-editing applications are bacteria's transcription of an immune system. When infected with a bacteria and virus use this piece of molecular machinery to form a concept of the intruder's genetic sequence so that, the next time that same virus outbreaks, CRISPR-Cas will immediately destroy and recognize it.

Viruses too have molecular methods up their sleeves, enabling some of them to combat CRISPR arguments. Newly, Alexander Meeske, a postdoctoral scholar in Luciano Marraffini's lab, discovered such a viral anti-CRISPR system that might be the common potent one yet reported. 

It works on a system called CRISPR-Cas13 that, unlike most other CRISPR systems, destroys a virus's RNA rather than its DNA. Helping with a team at Memorial Sloan Kettering CancerCenter, the researchers found that some viruses produce a protein described AcrVIA1, which shuts down the bacterial immune systems by fixing to a strategic place in the CRISPR-Cas13 device, preventing it of admitting the viral RNA.

Their practices revealed AcrVIA1 to be exceptionally powerful: Unlike other known anti-CRISPR proteins, it doesn't seem to rely on multiple viral infections to succeed. Colleagues and Marraffini found that even a single dose of AcrVIA1 could completely dismantle a bacterium's immunity.