CRISPR and Anti-CRISPR

The Topic

Researchers have discovered that bacteriophages—viruses that attack and can potentially kill bacteria—create and deploy proteins to neutralize CRISPR activity. CRISPR activity works essentially as an immune system for bacteria, fending off attack by bacteriophages.

The bacteriophages’ anti-CRISPR proteins could be applied in biotechnology to better control the activity of CRISPR systems in gene editing applications.

Graham Hatfull
Graham Hatfull

Our Expert's Take

“CRISPR-Cas systems [a gene-editing method] are now part of the common vernacular because of their utility for engineering genomes of many different organisms. CRISPR-Cas genes occur naturally in bacteria and fend off attack by bacteriophages,” said Graham Hatfull, professor of biological sciences in Pitt’s Dietrich School of Arts and Sciences, who studies the dynamics and interactions of bacteria and bacteriophages.

Anti-CRISPR proteins provide potent kill-switches for genetic engineers to shut down out-of-control CRISPR activity that can lead to unintended gene edits. Whenever using CRISPR-Cas to edit genomes, anti-CRISPR proteins can shut down the activity if it goes haywire, or alternatively can limit the activity to just a few specific cells in the body. 

“The key advantages of the CRISPR-Cas systems [that are being developed] is that they are both highly efficient and highly specific. The anti-CRISPRs don’t change that,” Hatfull said. “They just let you either shut down the activity in particular cells where you don’t want it occur, or let you shut the whole thing down, in circumstances where further editing events are undesirable.”