Targeted Nucleic Acid Editing via Cas9-Deaminase Fusion Proteins

Patent Status

Brief Description

Traditional genome editing relying on double-stranded DNA breaks (DSBs) can cause unintended indels, translocation events, and cytotoxic responses in target cells. To overcome these limitations, a precise site-specific modification technology is required that operates without inducing double-stranded DNA cleavage. Developed by UC Berkeley researchers, this technology utilizes engineered fusion proteins comprising a Cas domain (such as a Cas9 nickase or dCas9) integrated with a nucleic acid-editing enzyme domain, such as a deaminase. The molecular mechanism leverages the RNA-guided targeted binding capability of Cas9 to localize the enzymatic editing domain to a specific genomic locus, facilitating direct nucleotide alterations (e.g., cytidine or adenosine conversions) without introducing double-stranded cuts. This system delivers high-precision target modification, significantly reduces off-target insertion/deletion mutations, and improves cell viability during genomic modifications compared to conventional double-strand cleavage mechanisms.

Suggested uses

• Gene therapy for therapeutic correction of single-nucleotide genetic disorders in human cells

• Functional genomics and targeted gene disruption or regulation in biomedical research

• Development of genetically engineered crop varieties with specific agronomic traits

• Generation of cellular and animal disease models for high-throughput therapeutic screening

Advantages

• Enables precise nucleotide modification without introducing double-stranded DNA breaks

• Significantly lower rate of unintended insertion/deletion (indel) mutations relative to standard double-strand breaking enzymes

• High site-specificity driven by programmable RNA-guided Cas domains

• Broad applicability across eukaryotic, prokaryotic, and viral host systems

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