RNA interference-independent reprogramming of DNA methylation in Arabidopsis
RNA interference-independent reprogramming of DNA methylation in Arabidopsis
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DOI：
10.1038/s41477-020-00810-z
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发表时间：
2020-11-30
期刊：
影响因子：
18
通讯作者：
Kakutani, Tetsuji
中科院分区：
文献类型：
--
作者：
To, Taiko Kim;Nishizawa, Yuichiro;Kakutani, Tetsuji
揭示了一种基于染色质的、不依赖于rnai的机制，该机制在异染色质转座元件上重建DNA甲基化，并受到多种因素的影响，包括CG甲基化、H3K9去甲基化和H2A变体的替代。在包括植物在内的多种真核生物中，DNA甲基化对于沉默转座因子（TEs）非常重要。在植物基因组中，组蛋白H3赖氨酸9 （H3K9）和胞嘧啶的甲基化使te在CG和非CG环境中沉默。RNA干扰（RNAi）在建立te特异性沉默标记中的作用已被广泛研究，但RNAi独立通路的重要性仍未被广泛探索。在这里，我们直接研究了沉默标记丢失后te的跨代从头DNA甲基化。我们的分析揭示了在大多数TE基因（即TE内的编码区）中恢复非cg甲基化和H3K9甲基化的有效和精确的rnai独立途径。没有恢复的TE基因子集的特征揭示了H3K9去甲基化，组蛋白H2A变体的替代及其与CG甲基化的相互作用的影响，以及转录的反馈。这些染色质成分在真核生物中是保守的，可能以保守的方式参与染色质重编程。
A chromatin-based, RNAi-independent mechanism is uncovered that reestablishes DNA methylation on heterochromatin transposable elements and is impacted by multiple factors, including CG methylation, H3K9 demethylation and replacement of H2A variants.DNA methylation is important for silencing transposable elements (TEs) in diverse eukaryotes, including plants. In plant genomes, TEs are silenced by methylation of histone H3 lysine 9 (H3K9) and cytosines in both CG and non-CG contexts. The role of RNA interference (RNAi) in establishing TE-specific silent marks has been extensively studied, but the importance of RNAi-independent pathways remains largely unexplored. Here, we directly investigated transgenerational de novo DNA methylation of TEs after the loss of silent marks. Our analyses uncovered potent and precise RNAi-independent pathways for recovering non-CG methylation and H3K9 methylation in most TE genes (that is, coding regions within TEs). Characterization of a subset of TE genes without the recovery revealed the effects of H3K9 demethylation, replacement of histone H2A variants and their interaction with CG methylation, together with feedback from transcription. These chromatin components are conserved among eukaryotes and may contribute to chromatin reprogramming in a conserved manner.