BE-PLUS: a new base editing tool with broadened editing window and enhanced fidelity

Area of Science:

• Molecular Biology
• Gene Editing Technologies

Background:

• Base editors (BEs) utilize cytidine deaminases and catalytically defective Cas9 for base editing.
• The narrow editing window of conventional BEs restricts their application scope.

Purpose of the Study:

• To develop an improved base editing system with an expanded editing window.
• To enhance the precision and efficiency of C-to-T base editing.

Main Methods:

• Engineered a novel base editor named BE-PLUS by fusing GCN4 peptides to nCas9(D10A).
• Utilized the fusion to recruit scFv-APOBEC-UGI-GB1 to target sites for base editing.
• Evaluated the system's editing window, efficiency, and fidelity, including its application in gene disruption via iSTOP.

Main Results:

• BE-PLUS demonstrated a significantly broadened editing window, increasing genome-targeting scope.
• The system exhibited higher fidelity, with substantially fewer unwanted indels and non-C-to-T conversions.
• Successfully applied BE-PLUS for gene disruption across the genome by inducing stop codons.

Conclusions:

• BE-PLUS represents a novel base editing tool with an expanded editing capacity.
• The enhanced fidelity of BE-PLUS reduces off-target effects and improves editing outcomes.
• This technology offers a promising advancement for precise genome engineering applications.