在S相静音L1元件中父H3K9me3的不对称分布
Zhiming Li1,2,3,4, Shoufu Duan1,2,3,4, Xu Hua1,2,3,4
1Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA.
Nature
|November 8, 2023
概括
在复制过程中,基因组H3氨酸9三甲基化 (H3K9me3) 优先转移到领先的DNA链,特别是在LINE反转体中. 这种不对称的H3K9me3分布,由HUSH复合体和Pol ε介导,使重复的元素保持沉默.
科学领域:
- 表观遗传学
- 分子生物学
- 基因组学
背景情况:
- 在真核生物中,重复性DNA序列通过素H3 lysine 9三甲基化 (H3K9me3) 沉默.
- 失去这种沉默会导致基因组不稳定,癌症和衰老.
- 在DNA复制过程中H3K9me3分裂的机制仍然未知.
研究的目的:
- 研究父母H3K9me3在复制DNA链上的分离模式和机制.
- 了解H3K9me3在复制过程中如何分布在新合成的DNA中.
- 阐明H3K9me3不对称性在沉默重复元素中的作用.
主要方法:
- 使用细胞和分子生物学技术,研究了H3K9me3在复制分叉中的分布.
- 使用遗传方法研究HUSH复合体和DNA聚合酶Pol ε的作用.
- 分析了HUSH复合组件和Pol ε子单位对H3K9me3不对称性和重复元素表达的突变的影响.
主要成果:
- 在复制过程中,H3K9me3优先转移到领先的DNA链,特别是在长间隔的核元素 (LINE) 逆转移.
- 人类沉默枢纽 (HUSH) 复合体与DNA聚合酶Pol ε相互作用,以确保不对称的H3K9me3分离.
- 缺少Pol ε子单元或HUSH复合元件导致H3K9me3不对称和LINE表达增加.
结论:
- 在S阶段,HUSH复合物与Pol ε一起促进了H3K9me3在LINE上的不对称分布.
- 这种机制对于抑制重复元素的表达和保持基因组稳定性至关重要.
- 这些发现揭示了在DNA复制过程中表观遗传和基因沉默的新机制.
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