Molecular memory of prior infections activates the CRISPR/Cas adaptive bacterial immunity system

CRISPR/Cas (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated genes) is a small RNA-based adaptive prokaryotic immunity system that functions by acquisition of short fragments of DNA (mainly from foreign invaders such as viruses and plasmids) and subsequent destruction of DNA with sequences matching acquired fragments. Some mutations in foreign DNA that affect the match prevent CRISPR/Cas defensive function. Here we show that matching sequences that are no longer able to elicit defense, still guide the CRISPR/Cas acquisition machinery to foreign DNA, thus making the spacer acquisition process adaptive and leading to restoration of CRISPR/Cas-mediated protection. We present evidence…

• NI
  National Institutes of Health

  Award: GM59295
• RA
  Russian Academy of Sciences

  Award: GM59295