CRISPR–Cas adaptive immune systems are widespread among bacteria and archaea. Recent studies have shown that these systems have minimal long-term evolutionary effects in limiting horizontal gene transfer. This suggests that the ability to evade CRISPR–Cas immunity must also be widespread in phages and other mobile genetic elements. In this Progress article, we discuss recent discoveries that highlight how phages inactivate CRISPR–Cas systems by using anti-CRISPR proteins, and we outline evolutionary and biotechnological implications of their activity.
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A.P. was supported by a Canadian Institutes of Health Research Doctoral Award. Research in this area in the authors' laboratories is supported by Canadian Institutes of Health Research grants to A.R.D. (MOP-130482) and K.L.M. (MOP-136845).
The authors declare potential competing interest as all authors have a patent pending for anti-CRISPR technologies on which they are inventors.
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Pawluk, A., Davidson, A. & Maxwell, K. Anti-CRISPR: discovery, mechanism and function. Nat Rev Microbiol 16, 12–17 (2018). https://doi.org/10.1038/nrmicro.2017.120
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