Improve meat production and virus resistance by simultaneously editing multiple genes in livestock using Cas12i^(Max)

The clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated gene(Cas) system is continually optimized to achieve the most efficient gene editing effect. The Cas12i^(Max), a Cas12i variant, exhibits powerful DNA editing activity and enriches the gene editing toolbox. However, the application of Cas12i^(Max)in large domestic animals has not yet been reported. To verify the efficiency and feasibility of multiple gene editing in large animals, we generated porcine fibroblasts with simultaneous knockouts of IGF2, ANPEP, CD163,and MSTN via Cas12i^(Max)in one step. Phenotypically stable pigs were created through somatic cell nuclear transfer technology. They exhibited improved growth performance and muscle quality. Furthermore, we simultaneously edited three genes in bovine fibroblasts. A knockout of MSTN and PRNP was created and the amino acid Q-G in CD18 was precisely substituted. Meanwhile, no off-target phenomenon was observed by sum-type analysis or off-target detection. These results verified the effectiveness of Cas12i^(Max)for gene editing in livestock animals and demonstrated the potential application of Cas12i^(Max)in the field of animal trait improvement for agricultural production.