Part:BBa_K2558003

dCas9

Cas9 is the main protein of the CRISPR/Cas system II of Streptococcus pyogenes. CRISPR systems protect bacteria and archaea from phages by recognizing and cleaving of invading phage DNA. In practice, a short gRNA is used as a guide and bind the Cas9 protein to its complementary DNA strand. Cas9 protein would cleave the DNA strand at the binding site. dCas9 is a mutant of Cas9 that lacks DNase activity. dCas9 preserves the ability to bind gRNA and then to gRNA’s complementary DNA strand, but does not cut DNA double strands. Therefore dCas9/gRNA complex is able to inhibit expression without damaging DNA.