Bondy-Denomy, J. et al. Nature (2015) 526:136-139. http://www.ncbi.nlm.nih.gov/pubmed/26416740
The CRISPR/Cas gene editing system is based upon an adaptive bacterial immune system against bacteriophages. To overcome this immune system, phages have evolved proteins that inhibit CRISPR/Cas systems. The mode of inhibition varies by type of Cas system targeted, but usually involves inhibiting the formation of the DNA-Cas complex. Anti-Cas proteins might find use in gene editing techniques by modulating the activity of the Cas complex.