CRISPR-Cas adaptation: insights into the mechanism of action

Nat Rev Microbiol. 2016 Feb;14(2):67-76. doi: 10.1038/nrmicro.2015.14. Epub 2016 Jan 11.


Since the first demonstration that CRISPR-Cas systems provide bacteria and archaea with adaptive immunity against phages and plasmids, numerous studies have yielded key insights into the molecular mechanisms governing how these systems attack and degrade foreign DNA. However, the molecular mechanisms underlying the adaptation stage, in which new immunological memory is formed, have until recently represented a major unresolved question. In this Progress article, we discuss recent discoveries that have shown both how foreign DNA is identified by the CRISPR-Cas adaptation machinery and the molecular basis for its integration into the chromosome to form an immunological memory. Furthermore, we describe the roles of each of the specific CRISPR-Cas components that are involved in memory formation, and consider current models for their evolutionary origin.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adaptive Immunity / genetics
  • Adaptive Immunity / physiology
  • Animals
  • Archaea / genetics
  • Bacteria / genetics
  • Biological Evolution
  • CRISPR-Associated Proteins / genetics
  • CRISPR-Associated Proteins / metabolism*
  • CRISPR-Cas Systems / physiology*
  • Cell Cycle Proteins
  • Clustered Regularly Interspaced Short Palindromic Repeats / genetics
  • Clustered Regularly Interspaced Short Palindromic Repeats / physiology*
  • DNA / genetics*
  • DNA, Intergenic / genetics
  • Gene Expression Regulation / physiology
  • RNA / genetics
  • Repressor Proteins
  • Saccharomyces cerevisiae Proteins


  • CDC36 protein, S cerevisiae
  • CRISPR-Associated Proteins
  • Cell Cycle Proteins
  • DNA, Intergenic
  • Repressor Proteins
  • Saccharomyces cerevisiae Proteins
  • RNA
  • DNA