Fig. 1

CRISPR basic mechanism. CRISPR/Cas9 consists of cas9 and gRNA. Cas9 will cleave the sequence target directed by gRNA. gRNA composition is based on 3 components: PAM, gRNA scaffold, and gRNA spacer. PAM function is to initially recognize the sequence target to cut. gRNA scaffold function supports Cas9 binding. gRNA spacer role is to attach the sequence target for cleavage. Cleavage impact is homolog recombination and non-homolog end joining. Pros are it is easy to design and more efficient compared to other methods. Cons are off-target effect and not effective in every cell type