In Vivo Applications of Cell-Penetrating Zinc-Finger Transcription Factors

Nuclear and mitochondrial DNA editing in human cells with zinc finger deaminases

Base editing in nuclear DNA and mitochondrial DNA (mtDNA) is broadly useful for biomedical research, medicine, and biotechnology. Here, we present a base editing platform, termed zinc finger deaminases (ZFDs), composed of custom-designed zinc-finger DNA-binding proteins, the split interbacterial toxin deaminase DddA_tox, and a uracil glycosylase inhibitor (UGI), which catalyze targeted C-to-T base conversions without inducing unwanted small insertions and deletions (indels) in human cells. We assemble plasmids encoding ZFDs using publicly available zinc finger resources to achieve base editing at frequencies of up to 60% in nuclear DNA and 30% in mtDNA. Because ZFDs, unlike CRISPR-derived base editors, do not cleave DNA to yield single- or double-strand breaks, no unwanted indels caused by error-prone non-homologous end joining are produced at target sites. Furthermore, recombinant ZFD proteins, expressed in and purified from E. coli, penetrate cultured human cells spontaneously to induce targeted base conversions, demonstrating the proof-of-principle of gene-free gene therapy.

Base editing in nuclear DNA and mitochondrial DNA (mtDNA) is broadly useful for biomedical research, medicine, and biotechnology. Here the authors present zinc finger deaminases which catalyze targeted C-to-T base conversions without inducing unwanted indels in human cells.

Importance of two-dimensional cation clusters induced by protein folding in intrinsic intracellular membrane permeability

Two-dimensional cation clusters formed on the surface of proteins play an important role in their intracellular translocation.