Scientists pioneering CRISPR, a targeted gene editing tool that has revolutionized biotechnology, have discovered a naturally occurring ‘off-switch’ to control CRISPR activity. The discovery is positive for CRISPR researchers as it offers a natural solution to the concern of targeted CRISPR gene editing spiraling out of control. The ‘off-switch’ was found in small proteins encoded within bacteriophages (pictured): a viral genetic sequence that attacks cellular bacteria.
Bacteriophages (phage, from Greek ‘to devour’) are the most numerous viruses on Earth. Protein-shelled, they infect and self-replicate across bacterial networks, often killing bacteria in the process. CRISPR (clustered regularly interspaced short palindromic repeats) is a technique developed by bacteria in defense of bacteriophages infection, in which the bacteria’s genetic sequence self-modifies to produce immunity. Infected bacteria exhibit CRISPR when they incorporate genetic information from the virus into their DNA.
According to Science Magazine, the regulative proteins which can be used to regulate CRISPR activity probably emerged in bacteriophages as a way to counter bacteria defense systems. Incorporating anti-CRISPR proteins, bacteriophages can infect without risk of the host developing immunity.