L3V18

L3V18 is a high-fidelity CRISPR-Cas13d nuclease variant derived from *Ruminococcus flavefaciens* (RfxCas13d, also known as CasRx). Developed through structure-guided evolution and saturation mutagenesis of the HEPN catalytic domains and crRNA-binding pocket, L3V18 was engineered to address the safety concerns associated with target-activated collateral RNA cleavage. In preclinical studies, L3V18 demonstrated RNA targeting efficiency comparable to the wild-type enzyme while exhibiting no detectable collateral effects and significantly improved specificity over previous high-fidelity variants like N2V8. Its compact size makes it suitable for in vivo delivery via a single adeno-associated virus (AAV) vector, positioning it as a promising modality for programmable gene silencing and RNA-targeted gene therapy.