Compact zinc finger architecture utilizing toxin-derived cytidine deaminases for highly efficient base editing in human cells.

Fauser, Friedrich; Kadam, Bhakti N; Arangundy-Franklin, Sebastian; Davis, Jessica E; Vaidya, Vishvesha; Schmidt, Nicola J; Lew, Garrett; Xia, Danny F et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Nucleobase editors represent an emerging technology that enables precise single-base edits to the genomes of eukaryotic cells. Most nucleobase editors use deaminase domains that act upon single-stranded DNA and require RNA-guided proteins such as Cas9 to unwind the DNA prior to editing. However, the most recent class of base editors utilizes a deaminase domain, DddA<sub>tox</sub>, that can act upon double-stranded DNA. Here, we target DddA<sub>tox</sub> fragments and a FokI-based nickase to the human CIITA gene by fusing these domains to arrays of engineered zinc fingers (ZFs). We also identify a broad variety of Toxin-Derived Deaminases (TDDs) orthologous to DddA<sub>tox</sub> that allow us to fine-tune properties such as targeting density and specificity. TDD-derived ZF base editors enable up to 73% base editing in T cells with good cell viability and favorable specificity.

Medical subject headings