Rapid Multiplex Creation of Escherichia coli Strains Capable of Interfering with Phage Infection Through CRISPR.

In Escherichia coli, acquisition of new spacers in the course of CRISPR-Cas adaptation is dramatically stimulated by preexisting partial matches between a bacterial CRISPR cassette spacer and a protospacer sequence in the DNA of the infecting bacteriophage or plasmid. This phenomenon, which we refer to as "priming," can be used for very simple and rapid construction of multiple E. coli strains capable of targeting, through CRISPR interference, any phage or plasmid of interest. Availability of such strains should allow rapid progress in the analysis of CRISPR-Cas system function against diverse mobile genetic elements.