How Bacteria do not forget their enemies

Stan J.J. Brouns

Laboratory of Microbiology, Wageningen University, 6703 HB Wageningen, Netherlands.

ABSTRACT

The CRISPR immune system protects bacteria and archaea from invading viruses and plasmids. Immunity depends on a protein complex called Cascade, which uses small RNA molecules to find matching viral or plasmid DNA. Apart from giving insight into the unusual structure and function of Cascade, I will show how viruses escape immunity by mutating their DNA. A mechanism called priming takes care of these escaped viruses and will quickly update the memory of the immune system. I will highlight a single molecule FRET approach which has revealed insight into the target search mechanism of Cascade, and how Cascade differentially flags target DNA for either destruction, or for updating the memory of the immune system.

Fineran PC, Gerritzen MJ, Suárez-Diez M, Künne T, Boekhorst J, van Hijum SAFT, Staals RHJ,Brouns SJJ. Degenerate target sites mediate rapid primed CRISPR adaptation. Proc Natl Acad Sci U S A. 2014 Apr 22;111(16):E1629-38.

Blosser TR, Loeff L, Westra ER, Vlot M, Künne T, Sobota M, Dekker C, Brouns SJJ, Joo C. Two Distinct DNA Binding Modes Guide Dual Roles of a CRISPR-Cas Protein Complex. Mol Cell. 2015 Apr 2;58(1):60-70.