Off-target genomic DNA sites with partial complementarity to the MMAB guide RNA

Off-target genomic DNA sites with partial complementarity to the MMAB guide RNA represent unintended sequences in the genome that are susceptible to cleavage by CRISPR-Cas9 systems intended for the MMAB gene (Methylmalonic Aciduria Cobalamin Deficiency CblB Type). The MMAB gene encodes adenosine triphosphate:cob(I)alamin adenosyltransferase, which is essential for the synthesis of adenosylcobalamin (UniProt P58546). In therapeutic gene editing, a guide RNA (gRNA) is designed to target specific sequences within MMAB to correct mutations; however, Cas9 can tolerate mismatches, leading to double-strand breaks at off-target sites with similar sequences (Fu et al., 2013, Nature Biotechnology). These off-target effects are a primary safety concern in the development of gene therapies for methylmalonic aciduria, as they can lead to chromosomal translocations or the disruption of tumor suppressor genes (Kosicki et al., 2018, Nature Biotechnology). Monitoring these sites using methods like GUIDE-seq or CIRCLE-seq is mandatory for assessing the safety profile of CRISPR-based interventions (Tsai et al., 2015, Nature Biotechnology). Minimizing these interactions is critical for ensuring that the therapeutic benefit of correcting the MMAB locus outweighs the risk of secondary genomic damage.

Other names

CRISPR off-target sitesUnintended genomic cleavage sitesNon-specific gRNA binding sitesMMAB-specific off-target loci

Unintended DNA double-strand breaks (DSBs) caused by the Cas9 nuclease at genomic locations with sequence homology to the guide RNA (gRNA) designed for the MMAB gene.