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Gray DH, Santos J, Keir AG, Villegas I, Maddock S, Trope EC, Long JD, Kuo CY. A comparison of DNA repair pathways to achieve a site-specific gene modification of the Bruton's tyrosine kinase gene. Mol Ther Nucleic Acids 2022; 27:505-516. [PMID: 35036061 PMCID: PMC8728535 DOI: 10.1016/j.omtn.2021.12.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/09/2021] [Indexed: 01/08/2023]
Abstract
Gene editing utilizing homology-directed repair has advanced significantly for many monogenic diseases of the hematopoietic system in recent years but has also been hindered by decreases between in vitro and in vivo gene integration rates. Homology-directed repair occurs primarily in the S/G2 phases of the cell cycle, whereas long-term engrafting hematopoietic stem cells are typically quiescent. Alternative methods for a targeted integration have been proposed including homology-independent targeted integration and precise integration into target chromosome, which utilize non-homologous end joining and microhomology-mediated end joining, respectively. Non-homologous end joining occurs throughout the cell cycle, while microhomology-mediated end joining occurs predominantly in the S phase. We compared these pathways for the integration of a corrective DNA cassette at the Bruton's tyrosine kinase gene for the treatment of X-linked agammaglobulinemia. Homology-directed repair generated the most integration in K562 cells; however, synchronizing cells into G1 resulted in the highest integration rates with homology-independent targeted integration. Only homology-directed repair produced seamless junctions, making it optimal for targets where insertions and deletions are impermissible. Bulk CD34+ cells were best edited by homology-directed repair and precise integration into the target chromosome, while sorted hematopoietic stem cells contained similar integration rates using all corrective donors.
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Affiliation(s)
- David H. Gray
- Molecular Biology Interdepartmental Graduate Program, University of California, Los Angeles, CA 90095, USA
| | - Jasmine Santos
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Alexandra Grace Keir
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Isaac Villegas
- Division of Allergy and Immunology, Department of Pediatrics, David Geffen School of Medicine at the University of California, 10833 Le Conte MDCC 12-430, Los Angeles, CA 90095, USA
| | - Simon Maddock
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Edward C. Trope
- Division of Allergy and Immunology, Department of Pediatrics, David Geffen School of Medicine at the University of California, 10833 Le Conte MDCC 12-430, Los Angeles, CA 90095, USA
| | - Joseph D. Long
- Division of Allergy and Immunology, Department of Pediatrics, David Geffen School of Medicine at the University of California, 10833 Le Conte MDCC 12-430, Los Angeles, CA 90095, USA
| | - Caroline Y. Kuo
- Division of Allergy and Immunology, Department of Pediatrics, David Geffen School of Medicine at the University of California, 10833 Le Conte MDCC 12-430, Los Angeles, CA 90095, USA
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