Development of a Broadly Applicable Enzymatic Ligation Process for the Production of Single Guide RNAs

In this manuscript, we present a robust chemo-enzymatic approach for the production of single guide RNAs (sgRNAs), essential reagents for CRISPR-Cas9-based cell and gene therapy applications currently under development. Our method leverages ligase-mediated assembly of two RNA fragments, each synthesized using standard solid-phase chemistry. This versatile process has been applied, without modification, to produce a variety of GMP-grade sgRNAs, supporting our clinical ex vivo cell therapy pipeline. We demonstrate that our approach consistently achieves higher purity (10–15% improvement in LC-UV area%) and significantly greater yield (3–4 times higher) compared to traditional linear solid-phase synthesis, which is commonly used for sgRNA production. Importantly, the process utilizes T4 RNA ligase 2, a natural, nonengineered enzyme, which can be easily sourced from several vendors. We believe that openly sharing this method will drive significant progress in the development of cell and gene therapies, enabling the production of higher-quality sgRNAs at lower cost, ultimately improving accessibility and treatment outcomes for patients.