Zhang X, Van Treeck B, Horton CA, McIntyre JJR, Palm SM, Shumate JL, Collins K. Harnessing eukaryotic retroelement proteins for transgene insertion into human safe-harbor loci.
Nat Biotechnol 2024:10.1038/s41587-024-02137-y. [PMID:
38379101 DOI:
10.1038/s41587-024-02137-y]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 01/10/2024] [Indexed: 02/22/2024]
Abstract
Current approaches for inserting autonomous transgenes into the genome, such as CRISPR-Cas9 or virus-based strategies, have limitations including low efficiency and high risk of untargeted genome mutagenesis. Here, we describe precise RNA-mediated insertion of transgenes (PRINT), an approach for site-specifically primed reverse transcription that directs transgene synthesis directly into the genome at a multicopy safe-harbor locus. PRINT uses delivery of two in vitro transcribed RNAs: messenger RNA encoding avian R2 retroelement-protein and template RNA encoding a transgene of length validated up to 4 kb. The R2 protein coordinately recognizes the target site, nicks one strand at a precise location and primes complementary DNA synthesis for stable transgene insertion. With a cultured human primary cell line, over 50% of cells can gain several 2 kb transgenes, of which more than 50% are full-length. PRINT advantages include no extragenomic DNA, limiting risk of deleterious mutagenesis and innate immune responses, and the relatively low cost, rapid production and scalability of RNA-only delivery.
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