Genomic DNA at the sgRNA-specified locus (sgRNA-target DNA)

Genomic DNA at the sgRNA-specified locus refers to the precise chromosomal sequence targeted by CRISPR-Cas gene-editing systems for therapeutic modification. The specificity of this target is governed by a single guide RNA (sgRNA), which contains a 20-nucleotide spacer sequence that base-pairs with the complementary genomic DNA strand adjacent to a protospacer adjacent motif (PAM) (Jinek et al., Science, 2012). Upon binding, the Cas nuclease (e.g., Cas9 or Cas12a) creates a double-strand break (DSB) or, in the case of base editors, performs a chemical conversion of a specific nucleotide (Knott & Doudna, Science, 2018). This interaction is the fundamental mechanism for drugs like exagamglogene autotemcel, which targets the BCL11A erythroid-specific enhancer to treat sickle cell disease and beta-thalassemia (Frangoul et al., NEJM, 2021). The biological role of this target is to serve as the template for genetic repair or disruption, thereby altering the expression or function of the associated gene to achieve a therapeutic effect (Hsu et al., Cell, 2014). Ensuring high specificity for this locus is critical to avoid off-target effects, which remain a primary safety concern in the clinical application of these drugs (Fu et al., Nature Biotechnology, 2013). Successful targeting allows for permanent, curative changes to the genome, distinguishing this approach from traditional small molecule or protein-based therapies.

Other names

CRISPR target siteProtospacerGenomic target sequencesgRNA-directed locusTarget DNA

RNA-guided site-specific DNA modification via endonuclease cleavage or base editing