sgRNA

Small guide RNA(sgRNA) is a crucial component of the CRISPR gene knockout and knock-in system. Initially discovered guide RNA consists of two parts: tracRNA and crRNA. When these two parts are fused and expressed together, the resulting sgRNA can effectively perform the guide function by combining with the Cas9 protein and directing the Cas9 enzyme to target and cut genomic DNA.

Commonly used sgRNA is transfected into cells in plasmid form. It can be designed either on the same plasmid with the Cas protein or on separate plasmids. However, unless packaged into a virus, either method results in low editing efficiency due to the large plasmid fragments, and there is a higher risk of off-target effects and carcinogenicity.

These issues are completely avoided by using sgRNA oligos. Chemically synthesized sgRNA can form ribonucleoprotein complexes (RNPs) with Cas9 protein in vitro. Compared to other delivery methods, RNPs exhibit higher editing efficiency, lower off-target effects, and minimal immunogenicity.