Genomic DNA target sequence

The genomic DNA sequence complementary to the delivered single guide RNA (sgRNA) serves as the precise molecular target for CRISPR-based gene editing systems (Jinek et al., 2012, Science). This sequence, typically referred to as the protospacer, is recognized by the Cas-sgRNA ribonucleoprotein complex through Watson-Crick base pairing, provided it is adjacent to a specific Protospacer Adjacent Motif (PAM) (Doudna & Charpentier, 2014, Science). Upon successful hybridization, the Cas effector protein (e.g., Cas9, Cas12a) induces a double-strand break or performs targeted chemical modifications, such as base editing or prime editing, at the specific locus (Knott & Doudna, 2018, Science). This interaction is the fundamental mechanism for therapeutic gene modulation, allowing for the permanent disruption of deleterious genes or the correction of hereditary mutations. Clinically, this target is utilized in therapies such as exagamglogene autotemcel (Casgevy), which targets the BCL11A enhancer to treat sickle cell disease and beta-thalassemia (FDA, 2023). The primary therapeutic challenge associated with this target is ensuring high specificity to prevent off-target activity, which can lead to unintended genomic alterations and potential oncogenic risks (Fu et al., 2013, Nature Biotechnology).

Other names

ProtospacerCRISPR target sitesgRNA-binding siteTarget DNA locusGenomic target sequence

RNA-guided site-specific DNA binding and cleavage or modification.