Genome-wide off-target DNA sites with partial complementarity to the APOE4 guide RNA

Genome-wide off-target DNA sites with partial complementarity to the APOE4 guide RNA represent a significant safety concern in the development of gene therapies for Alzheimer's disease. The Apolipoprotein E epsilon 4 (APOE4) allele is a major genetic risk factor for neurodegeneration, and researchers utilize CRISPR-Cas9 or base editing technologies to modify or silence this allele (Corder et al., 1993, Science). However, the guide RNA (gRNA) designed to recognize the APOE4 sequence may also bind to other regions of the genome that possess similar nucleotide sequences, leading to unintended double-strand breaks or base substitutions (Fu et al., 2013, Nature Biotechnology). These off-target effects can result in permanent mutations, potentially inactivating tumor suppressor genes or activating oncogenes, which poses a risk of malignancy (Tsai et al., 2015, Nature Biotechnology). Consequently, identifying and characterizing these sites using high-throughput sequencing methods like GUIDE-seq is essential for ensuring the precision and safety of APOE4-targeted interventions (Zhao et al., 2020, Cell Reports). Monitoring these sites allows for the optimization of gRNA design and the selection of high-fidelity Cas variants to minimize clinical risk.

Other names

CRISPR off-target sitesNon-specific DNA cleavage sitesAPOE4 gRNA mismatchesUnintended genomic modifications

Unintended DNA binding and enzymatic modification (cleavage or base conversion) by a CRISPR-based system at genomic loci sharing sequence similarity with the APOE4 target sequence.