The Role of Recombinant AAV in Precise Genome Editing

Abstract

The replication-defective, non-pathogenic, nearly ubiquitous single-stranded adeno-associated viruses (AAVs) have gained importance since their discovery about 50 years ago. Their unique life cycle and virus-cell interactions have led to the development of recombinant AAVs as ideal genetic medicine tools that have evolved into effective commercialized gene therapies. A distinctive property of AAVs is their ability to edit the genome precisely. In contrast to all current genome editing platforms, AAV exclusively utilizes the high-fidelity homologous recombination (HR) pathway and does not require exogenous nucleases for prior cleavage of genomic DNA. Together, this leads to a highly precise editing outcome that preserves genomic integrity without incorporation of indel mutations or viral sequences at the target site while also obviating the possibility of off-target genotoxicity. The stem cell-derived AAV (AAVHSCs) were found to mediate precise and efficient HR with high on-target accuracy and at high efficiencies. AAVHSC editing occurs efficiently in post-mitotic cells and tissues in vivo. Additionally, AAV also has the advantage of an intrinsic delivery mechanism. Thus, this distinctive genome editing platform holds tremendous promise for the correction of disease-associated mutations without adding to the mutational burden. This review will focus on the unique properties of direct AAV-mediated genome editing and their potential mechanisms of action.

Genome Editing for Sustainable Crop Improvement and Mitigation of Biotic and Abiotic Stresses

“…For example, D’Halluin et al [ 32 ] inserted multiple trait genes, 4-hydroxyphenylpyruvate dioxygenase ( hppd ) and modified enol-pyruvylshikimate-3-phosphate synthase genes ( epsps ) into cotton using meganucleases to enhance its herbicide tolerance. Although meganucleases have been successfully applied for targeted gene editing in the plant, they have a few limitations, such as the low catalytic activity of the enzyme, prone to sequence degeneracy, and the lack of mature DNA binding structure, which hinders their wide applications [ 33 , 34 ].…”

Development of an AAV DNA-based synthetic vector for the potential gene therapy of hemophilia in children

“…This was understood to be the possible result of the ITR sequence itself as it was previously found that WT-ITR containing constructs have repressed gene expression as opposed to those without ITR sequences. This is because AAV ITRs can bind to the double-strand break pathway protein ataxia-telangiectasia mutated (ATM), which can repress gene expression directly ( Bijlani et al, 2022 ). Additionally, the activation of the ATM due to the presence of ITRs can induce cell cycle arrest and apoptosis ( Pusapati et al, 2006 ).…”

Genome Editing for Sustainable Crop Improvement and Mitigation of Biotic and Abiotic Stresses

“…Although meganucleases have been successfully applied for targeted gene editing in the plant, they have a few limitations, such as the low catalytic activity of the enzyme, prone to sequence degeneracy, and the lack of mature DNA binding structure that hinders their wide applications [28,29].…”