Extended Data Fig. 9: Strategies to improve the specificity of DdCBE.
From: Mitochondrial base editor induces substantial nuclear off-target mutations
a, Fusing nuclear export signal (NES) sequences into the DdCBE constructs. The protein level of DdCBE in the nucleus should be decreased, and hence lower the risk of nDNA off-target editing. b, Co-expressing DddIA that fused with nuclear localization signals (NLS). DddIA is a natural immunity protein of the deaminase DddA; bpNLS-linked DddIA is supposed to antagonize the deamination activity of DdCBEs mis-localized into the nucleus. bpNLS, bipartite NLS at both the N and C termini. c, Mutating the DddAtox in the DdCBE architecture to reduce its intrinsic DNA binding affinity. Ideally, mutated deaminase would not be able to catalyze DNA substrates without the help of simultaneously stable binding of the two TALE repeats.
