Frequent endonuclease cleavage at off-target locations in vivo

Area of Science:

• Molecular Biology
• Genetics
• Biotechnology

Background:

• Targeted DNA breaks are essential for increasing recombination frequencies in gene editing.
• The specificity of enzymes like rare-cutting endonucleases is critical, especially for clinical applications.
• Off-target cleavage events can have significant consequences in therapeutic settings.

Purpose of the Study:

• To investigate the specificity of the I-SceI endonuclease.
• To identify noncanonical cleavage sites of I-SceI in the human genome.
• To emphasize the importance of in vivo characterization of enzyme cleavage specificity.

Main Methods:

• Localization of adeno-associated virus (AAV) vector-chromosome junctions.
• Analysis of cleavage events within the human genome.
• In vivo characterization of enzyme activity.

Main Results:

• Identification of frequently cut noncanonical cleavage sites for I-SceI.
• Demonstration of off-target cleavage events in the human genome.
• Evidence of I-SceI activity at unexpected genomic locations.

Conclusions:

• The specificity of I-SceI is not limited to its canonical recognition site.
• In vivo analysis is essential for a comprehensive understanding of enzyme cleavage patterns.
• Findings have implications for the safety and efficacy of gene-editing therapies using rare-cutting endonucleases.