Fig. 1
From: CRISPR/Cas9 revitalizes adoptive T-cell therapy for cancer immunotherapy
The most prominent genome editing platforms for DSB induction and its subsequent repair. ZFNs (a) and TALENs (b) utilize their respective DNA-binding domain to distinguish target sequences and form a dimer. Dimerized FokI proceeds to cleave the sequence. Cas9-related DSB generation requires a PAM sequence (c). NHEJ and/or HDR can both participate in repairing the DSBs (d). In the absence of donor DNA, NHEJ repair results in gene knockout. When donor DNA is available, it is cleaved by the nucleases at the same time, producing overhangs consistent with the cleaved target sequence. NHEJ uses this template to fill the gap and produce knock-ins (e). Similarly, HDR can repair DSBs to insert or correct genes when donor DNA is present but with more precise substitution (f)