Dna2核酶缺陷导致染色体断裂的大型和复杂的DNA插入
Yang Yu1, Nhung Pham1, Bo Xia2,3,4
1Baylor College of Medicine, Department of Molecular and Human Genetics, Houston, TX, USA.
Nature
|December 7, 2018
概括
缺乏Dna2核酶的酵母突变经常将DNA片段插入双链断裂 (DSB). 这些来自不同基因组区域的插入代表了依赖于非同类末端连接和Pol4的重复.
科学领域:
- 遗传学
- 分子生物学
- 基因组学
背景情况:
- 在DNA双链断裂 (DSB) 中插入移动元素,线粒体DNA和核染色体碎片威胁到基因组完整性,并且在癌症中很普遍.
- 在DSB中染色体片段插入的起源和预防机制在很大程度上是未知的.
研究的目的:
- 调查在DSB中插入DNA片段的机制.
- 确定这些插入的片段的基因组起源和特征.
- 阐明防止这种插入所涉及的细胞通路.
主要方法:
- 缺乏进化保存的Dna2核酶的酵母突变的特征.
- 在DSB中发现的大约500个DNA插件的测序.
- 对这些重复对非同类末端连接 (NHEJ) 和Pol4的依赖性的分析.
主要成果:
- 缺少Dna2的酵母突变体经常在DSB中插入DNA序列 (0.11.5 kb),通常涉及多个连接的片段.
- 插入的片段来源于Ty逆转移 (8%),核糖体DNA (rDNA) (15%) 和其他基因组区域,偏好脆弱的部位.
- 这些插入代表重复,因为原始位置保持完整,并依赖于NHEJ和Pol4.
结论:
- 在Dna2缺乏的细胞中,DNA结构的替代处理可以导致片段释放和随后在DSB捕获.
- 这种机制为染色体片段插入的起源提供了洞察力.
- 在任何具有线性染色体外DNA片段的细胞类型中都可能发生类似的DNA插入.
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