Single guide RNA (sgRNA) (sgRNA)

Single guide RNA (sgRNA) is a synthetic, engineered RNA molecule that serves as the programmable component of the CRISPR-Cas9 genome editing system. It is created by fusing the naturally occurring CRISPR RNA (crRNA), which provides sequence specificity, and the trans-activating CRISPR RNA (tracrRNA), which acts as a scaffold for the Cas9 nuclease (Jinek et al., 2012). The sgRNA contains a 20-nucleotide spacer sequence that is complementary to a specific target DNA site, allowing the Cas9 enzyme to be precisely directed to a genomic location for cleavage or modification (Synthego, 2025). In therapeutic applications, sgRNAs are designed to target disease-causing genes, such as the BCL11A enhancer in sickle cell disease or viral DNA in chronic infections (ClinicalTrials.eu, 2023). As a critical element of the first FDA-approved CRISPR therapy, exagamglogene autotemcel, sgRNA technology represents a paradigm shift in precision medicine by enabling the direct correction of genetic defects (Digitell, 2024). Beyond simple cleavage, sgRNAs can be used with modified Cas proteins to activate or repress gene expression, providing a versatile platform for treating complex diseases.

Other names

sgRNAchimeric guide RNAsynthetic guide RNAgRNA

The sgRNA directs a Cas nuclease (e.g., Cas9) to a specific genomic DNA sequence through Watson-Crick base pairing of its 20-nucleotide spacer region (Jinek et al., 2012). It forms a ribonucleoprotein (RNP) complex with the nuclease, which then induces a site-specific double-strand break (DSB) or other genetic modification at the target locus adjacent to a protospacer adjacent motif (PAM) (Synthego, 2025).