Fig. 1
From: New insights on CRISPR/Cas9-based therapy for breast Cancer
How CRISPR/Cas9 works as immune system in bacteria. When the invader (plasmid or virus) enters bacteria [1], it directs a nuclease called Cas2 to snip a short sequence of the viral genome (spacer) [2] and insert it between two repeats in its CRISPR locus [3]. When this invader type come again [4], the bacteria transcribe its spacer to generate crRNA [5], which will be matured by tracrRNA. Both types of RNA associated with Cas9 [6] will be directed to the invader genome to cleave it (using Cas9) after recognizing it (using crRNA) [7]