Production of virus-like particles with AsCas12a nuclease and CMV-driven crRNA for mammalian genome editing.

CRISPR/Cas genome editing tools represent a promising technology for biomedicine with significant therapeutic potential for numerous human diseases. However, efficient delivery of these tools into primary cells, particularly in the form of ribonucleoprotein (RNP) complexes, remains a critical bottleneck that limits clinical translation. Virus-like particles (VLPs) derived from human immunodeficiency virus type 1 (HIV-1) or murine leukemia virus (MLV) have emerged as promising delivery vehicles for RNP complexes, yet their activity is limited by suboptimal nuclease and guide RNA packaging. Previously, we generated NanoMEDIC VLPs incorporating the AsCas12a nuclease with CMV-driven crRNA, which demonstrated substantially enhanced editing efficiency over SpCas9-VLPs with U6-driven gRNA. Here, we describe a detailed protocol for a small-scale production of AsCas12a-VLPs using three distinct transfection methods [cationic lipids, polyethyleneimine (PEI), and calcium-phosphate] and a large-scale production of VLPs using calcium-phosphate transfection. We show that both production scales yield comparable nuclease loading into VLPs and similar editing efficiencies, reaching up to 60% of CXCR4 knockout in Jurkat T cells.