FLICKR, NATURALISMUS Diverse groups of bacterial species encode genes that block the activity of specific CRISPR/Cas systems, according to a team from the University of Toronto and the University of Otago, New Zealand. Scanning prophages (genomes of bacteriophages integrated within bacterial genomes), Toronto’s Alan Davidson and colleagues have identified five new protein-coding anti-CRISPR genes, adding to the list of nine his group had previously identified. The team’s latest work, published today (June 13) in Nature Microbiology, highlights a way to learn how CRISPR systems work as well as a potential add-on tool for CRISPR-based gene editing.
“The authors report a beautiful application of the Red Queen theory, which posits that there is a kind of an arms race between all living organisms, and between the host and parasite in particular,” said Didier Raoult, a microbiologist at Aix-Marseille University in France who was not involved in the work. These proteins “are the phages’ answers to bacterial CRISPR systems which are a form of aggression by the bacteria,” he added.
“The discovery of anti-CRISPR proteins is not surprising in the sense that phage must develop these as part of the nature of the host-parasite co-evolution,” said Eugene Koonin of the US National Center for Biotechnology Information and the National Library of Medicine.
Davidson’s team in 2013 found that a single prophage within the ...
