Zinc finger nuclease (ZFN)

Zinc finger nucleases (ZFNs) are a class of engineered DNA-binding proteins designed to facilitate targeted genome editing by creating site-specific double-strand breaks (DSBs) in DNA [1]. These chimeric proteins consist of a tandem array of zinc finger motifs, which are customized to recognize and bind to specific DNA sequences, fused to the non-specific cleavage domain of the FokI restriction endonuclease [2]. To cleave DNA, two ZFN monomers must bind to adjacent sites on opposite DNA strands, allowing the FokI domains to dimerize and activate their catalytic activity [3]. This high degree of specificity makes ZFNs a powerful tool for therapeutic interventions, such as disrupting the CCR5 receptor to provide resistance to HIV infection or correcting monogenic mutations in liver-directed therapies [4]. In clinical applications, ZFNs are often delivered as mRNAs, proteins, or via viral vectors like AAV to target specific tissues or ex vivo cell populations like T-cells or hematopoietic stem cells [5]. The induction of a DSB triggers endogenous cellular repair pathways, namely non-homologous end joining (NHEJ) for gene disruption or homology-directed repair (HDR) for precise gene editing [1]. While ZFNs were the first major platform for precision genome engineering, they face competition from newer technologies like CRISPR/Cas9. However, they remain a significant modality in clinical trials for metabolic diseases and infectious diseases due to their established safety profile and high specificity achieved through protein engineering [4][6]. Sources: [1] Urnov, F. D., et al. (2010). 'Genome editing with engineered zinc finger nucleases.' Nature Reviews Genetics, 11(9), 636-646. [2] Kim, Y. G., et al. (1996). 'Hybrid restriction enzymes: Zinc finger fusions to Fok I cleavage domain.' PNAS, 93(3), 1156-1160. [3] Carroll, D. (2011). 'Genome engineering with zinc-finger nucleases.' Genetics, 188(4), 773-782. [4] Tebas, P., et al. (2014). 'Gene editing of CCR5 in autologous CD4 T cells of persons with HIV.' New England Journal of Medicine, 370(10), 901-910. [5] Porteus, M. H. (2016). 'Genome Editing: A New Era in Genetic Correction.' Molecular Therapy, 24(3), 430-444. [6] NIH Genetic Modification Clinical Research Information System (GeMCRIS) database.

Other names

Zinc-finger nucleaseZFP-nucleaseEngineered zinc finger nucleaseZinc finger protein nuclease

ZFNs function as dimers to induce site-specific double-strand breaks (DSBs) in genomic DNA. The DNA-binding domain recognizes specific sequences, and the FokI nuclease domain catalyzes cleavage. The resulting DSB is repaired by the cell's natural machinery via non-homologous end joining (NHEJ), which can knock out a gene, or homology-directed repair (HDR), which can insert or correct a genetic sequence using a provided template.