Invention Title:

CONTEXT-SPECIFIC ADENINE BASE EDITORS AND USES THEREOF

Publication number:

US20250333718

Publication date:

2025-10-30

Section:

Chemistry; metallurgy

Class:

C12N9/78

Inventors:

David R. Liu 🇺🇸 Cambridge, MA, United States

Kevin Tianmeng Zhao 🇺🇸 Cambridge, MA, United States

Assignees:

President and Fellows of Harvard College 🇺🇸 Cambridge, MA, United States

THE BROAD INSTITUTE, INC. 🇺🇸 Cambridge, MA, United States

Applicants:

PRESIDENT AND FELLOWS OF HARVARD COLLEGE 🇺🇸 Cambridge, MA, United States

The Broad Institute, Inc. 🇺🇸 Cambridge, MA, United States

Smart overview of the Invention

The disclosure presents adenine base editors (ABEs) with context specificity, showing preference for either pyrimidine or purine nucleotides positioned 5′ of the target adenosine. These ABEs are designed for precise nucleic acid editing, minimizing off-target effects known as bystander edits. The invention includes pharmaceutical compositions containing the ABEs and vectors for their delivery and engineering through directed evolution.

Innovative Features

ABEs are engineered to correct pathogenic point mutations by converting A•T base pairs to G•C base pairs without causing double-stranded DNA breaks. Context-specific ABEs reduce bystander edits, enhancing the precision of therapeutic applications. The disclosure also introduces complexes of these base editors with guide RNA, polynucleotides, vectors, and kits for effective application in targeted editing.

Technical Advancements

Recent advancements involve fusing adenosine deaminase to a nucleic acid programmable DNA binding protein domain, improving editing efficiency. Some ABEs demonstrate reduced bystander editing while maintaining high on-target efficiency, with some achieving near-zero bystander editing frequencies. This evolution enhances targeting scope and product purity.

Research and Development

The development of these ABEs involves evolving adenosine deaminase TadA8e using phage-assisted methods to select for nucleotide preferences at the 5′ position. These methods focus on reducing bystander edits and improving targeting scope. The invention capitalizes on previous research involving variants like ABE7.10 and ABE8c to enhance efficiency and specificity.

Applications and Implications

This innovation enables precise correction of nearly half of known pathogenic point mutations, offering significant potential in therapeutic settings. By enhancing the specificity and efficiency of ABEs, the technology addresses limitations of previous base editors, paving the way for more accurate genetic interventions with minimized off-target effects.