Saito Shinta, Suzuki Tetsuya, Nohmi Takehiko, Adachi Noritaka
Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Yokohama 236-0027, Japan.
Department of Nucleic Acids Biochemistry, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan.
Proc Natl Acad Sci U S A. 2025 Jun 17;122(24):e2508507122. doi: 10.1073/pnas.2508507122. Epub 2025 Jun 9.
Efficient targeted integration (TI) of homologous donor DNA is crucial for precise genome editing. Although mismatch repair (MMR) is known to suppress TI as well as homologous recombination (HR) when sequence divergence is present, it remains controversial as to whether MMR affects TI of isogenic donor DNA. In this study, we investigated whether and how the MMR protein Msh2 affects TI of isogenic donor DNA. We found that HR-dependent TI is suppressed by Msh2 only when a homology arm of donor DNA is as short as 1.7 kb. In contrast, single-strand annealing-mediated TI, which is cell cycle-independent and becomes prominent when HR or non-homologous end joining is inactivated, is weakly but constantly affected by Msh2 irrespective of the size of homology arms. Our results reveal a previously unrecognized type of HR suppression by Msh2 and provide implications for precise genome editing using short-arm donor DNA vectors.
同源供体DNA的高效靶向整合（TI）对于精确的基因组编辑至关重要。尽管已知错配修复（MMR）在存在序列差异时会抑制TI以及同源重组（HR），但MMR是否影响同基因供体DNA的TI仍存在争议。在本研究中，我们调查了MMR蛋白Msh2是否以及如何影响同基因供体DNA的TI。我们发现，仅当供体DNA的同源臂短至1.7 kb时，Msh2才会抑制依赖HR的TI。相比之下，单链退火介导的TI不依赖细胞周期，并且在HR或非同源末端连接失活时变得突出，无论同源臂的大小如何，它都受到Msh2的微弱但持续的影响。我们的结果揭示了Msh2以前未被认识到的一种HR抑制类型，并为使用短臂供体DNA载体进行精确的基因组编辑提供了启示。
Zotero 插件