TESOGENASE, An Engineered Nuclease Editor for Enhanced Targeted Genome Integration

Summary/AbstractNon-viral DNA donor template has been widely used for targeted genomic integration by homologous recombination (HR). This process has become more efficient with RNA guided endonuclease editor system such as CRISPR/Cas9. Circular single stranded DNA (cssDNA) has been harnessed previously as a genome engineering catalyst (GATALYST) for efficient and safe targeted gene knock-in. However, the engineering efficiency is bottlenecked by the nucleoplasm trafficking and genomic tethering of cssDNA donor, especially for extra-large transgene integration. Here we developed enGager, enhanced GATALYST associated genome editor system by fusion of nucleus localization signal (NLS) peptide tagged Cas9 with various single stranded DNA binding protein modules through a GFP reporter Knock-in screening. The enGager system assembles an integrative genome integration machinery by forming tripartite complex for engineered nuclease editors, sgRNA and ssDNA donors, thereby facilitate the nucleus trafficking of DNA donors and increase their active local concentration at the targeted genomic site. When applied for genome integration with cssDNA donor templates to diverse genomic loci in various cell types, these enGagers outperform unfused editors. The enhancement of integration efficiency ranges from 1.5- to more than 6-fold, with the effect being more prominent for > 4Kb transgene knock-in in primary cells. We further demonstrated that enGager mediated enhancement for genome integration is ssDNA, but less dsDNA dependent. Using one of the mini-enGagers, we demonstrated large chimeric antigen receptor (CAR) transgene integration in primary T cells with exceptional efficiency and anti-tumor function. These tripartite editors with ssDNA optimized genome engineering system (TESOGENASETM) add a set of novel endonuclease editors into the gene-editing toolbox for potential cell and gene therapeutic development based on ssDNA mediated non-viral genome engineering. HighlightO_LIA reporter Knock-in screening establishes enGager system to identify TESOGENASE editor to improving ssDNA mediated genome integration C_LIO_LIMini-TESOGENASEs developed by fusing Cas9 nuclease with novel ssDNA binding motifs C_LIO_LImRNA mini-TESOGENASEs enhance targeted genome integration via various non-viral delivery approaches C_LIO_LIEfficient functional CAR-T cell engineering by mini-TESOGENASE C_LI