独特的H3K9me3异染色体维护动态控制了多能细胞中不同的基因程序和重复
Jingchao Zhang1,2,3, Greg Donahue1,2,3, Michael B Gilbert2,4
1Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, USA.
Nature cell biology
|November 1, 2024
概括
基因组H3氨酸9三甲基化 (H3K9me3) 异染色素稳定性在整个基因组中各不相同. 它的衰变涉及被动和活性机制,由黑色素蛋白1 (HP1) 和氨酸甲基转移酶 (KMTs) 调节.
科学领域:
- 表观遗传学和基因调控
- 染色体生物学 染色体生物学
- 干细胞生物学 干细胞生物学
背景情况:
- 对于抑制血统基因和DNA重复至关重要的H3K9me3异色素,由KMTs建立,并由HP1.1压缩.
- 以前对H3K9me3异染色素稳定性的理解仅限于特定的基因组区域和DNA重复.
研究的目的:
- 为了研究H3K9me3异染色素全基因组的动态和稳定性.
- 确定控制H3K9me3衰变和异色素蛋白维护的因素和机制.
- 阐明色胺蛋白1 (HP1) 在色胺稳定性和多能性中的作用.
主要方法:
- 工程 Suv39h2-淘汰赛小鼠胚胎干细胞快速耗尽H3K9me3 KMTs.
- 在整个基因组中分析了H3K9me3衰变速率和相关的染色质特征.
- 研究了异染色蛋白1 (HP1) 解离及其对转录因子结合和染色素可访问性的影响.
主要成果:
- 确定了四种不同的H3K9me3衰变速率,受色素特征和转录因子结合的影响.
- 证明了被动稀释和积极去除都会在12-24小时内导致H3K9me3的衰变.
- 揭示了一种"二进制开关"机制,其中HP1在KMT耗尽时迅速解离,限制了先驱因子结合和多能性退出.
结论:
- H3K9me3异染色体维护在整个基因组中表现出不同的动态,控制基因网络和重复.
- HP1在异染色质缩和保护多能性方面发挥着至关重要的作用.
- 退缩的H3K9me3域可以显示剩余的HP1丰富,表明复杂的异染色素调节.
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