该研究 通过系统性功能筛选，开发了一种基于 微生物来源 EcRecE 核酸外切酶 的精准基因编辑工具—— Cas9-EcRecE ， 该编辑系统 在哺乳动物细胞中 显著 提 高 长片段 DNA （ 千碱基级 ） 的精准插入效率 。同时，基于 dCas9 ，该研究进一步构建了 无 需依赖 DNA 双链断裂 （DSB） 的安全 基因组编辑工具 —— dCas9-EcRecTE ，为实现安全高效的基因编辑提供新的技术支持 。 编辑丨王多鱼 排版丨水成文 CRISPR/Cas9 基因编辑 技术 已成为 21 世纪生物医学领域最具突破性的 基因编辑工具， 在基础研究和转化医学方面展现巨大潜力。然而， CRISPR/Cas9 技 术仍面临许多亟须解决的技术挑战。其一，精准且安全编辑挑战。 CRISPR/Cas9 技术依赖基因组 DNA 双链断裂 （ DSB ） 或单链断裂 （ SSB ） 来介导基因 编辑事件发生。断裂的 DNA 极易 诱发非同源末端连接 （ NHEJ） 修复通路 ，进一步 引发潜在的基因组不稳定性和细胞毒性效应。 其二，长片段高效插入挑 战。 现有基因编辑工具大多用于短序列 DNA 片段的插入或编辑 ， ...

Core Insights - A research team from Mie University and other institutions in Japan has successfully utilized gene editing technology to remove the extra 21st chromosome from cells of patients with Down syndrome, confirming the results in a publication in the Proceedings of the National Academy of Sciences [1][2] Group 1: Research Methodology - The team extracted fibroblasts from the skin of Down syndrome patients to cultivate induced pluripotent stem cells (iPS cells) [2] - They developed three types of iPS cells, each with one of the three 21st chromosomes deleted, and constructed a CRISPR/Cas9 system to target and cut the extra chromosome at multiple sites [2] - The CRISPR/Cas9 system achieved a removal accuracy of up to 37.5% for the target 21st chromosome [2] Group 2: Findings and Implications - Analysis of the modified iPS cells showed that their characteristics, including gene expression patterns, cell proliferation rates, and reactive oxygen handling, had returned to normal [2] - The CRISPR/Cas9 system was also confirmed to be effective in removing chromosomes from differentiated cells, such as fibroblasts and non-dividing cells [2] Group 3: Future Directions - The technology is currently in the concept validation stage through in vitro cell experiments and has some limitations [2] - Future research will focus on developing safer chromosome removal techniques that do not rely on cutting [2]