High-fidelity enhanced AsCas12a knock-in mice for efficient multiplexed gene editing, disease modeling and orthogonal immunogenetics

The advancement of CRISPR gene editing technology, especially the development of Cas9 knock-in mice, has significantly boosted the functional discovery of various genetics factors in diverse fields including genetics, genomics, immunology, and the biology of cancer. However, the pleiotropic effects on human disease and the complex nature of gene interaction networks require a knock-in mouse model capable of simultaneous multiplexed gene perturbation. Here, we present the generation and applications of Cre-dependent conditional and constitutive high-fidelity, enhanced AsCas12a (enAsCas12a-HF1) Rosa26-knock-in mice in the C57BL/6 background. With these mouse strains, we demonstrate highly efficient and multiplexed in vivo and ex vivo genome engineering as applied to lipid nanoparticle (LNP)-RNA-based liver protein targeting, AAV-based tumor modeling, and retrovirus-based immune cell engineering. By integrating with a dCas9-SPH CRISPR activation transgenic strain, we establish a simultaneous dual gene activation and knockout (DAKO) system that showcases the modular potential of these enAsCas12a-HF1 mice. Importantly, constitutive expression of enAsCas12a-HF1 does not lead to any discernable pathological differences as compared to the C57BL/6 background strain. These knock-in mice and the accompanying delivery methods would empower the deconvolution of complex gene interaction networks in broad areas of research.