Propagation of patterns of gene expression through the cell cycle requires prompt restoration of epigenetic marks after the twofold dilution caused by DNA replication. Here we show that the transcriptional repressive mark H3K27me3 (histone H3 lysine 27 trimethylation) is restored in replicating plant cells through DNA replication–coupled modification of histone variant H3.1. Plants evolved a mechanism for efficient K27 trimethylation on H3.1, which is essential for inheritance of the silencing memory from mother to daughter cells. We illustrate how this mechanism establishes H3K27me3-mediated silencing during the developmental transition to flowering. Our study reveals a mechanism responsible for transmission of H3K27me3 in plant cells through cell divisions, enabling H3K27me3 to function as an epigenetic mark.

中文翻译：

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DNA复制耦合的组蛋白修饰可维持植物中的Polycomb基因沉默

通过细胞周期传播基因表达模式需要在DNA复制引起的两倍稀释后迅速恢复表观遗传标记。在这里，我们显示转录抑制标记H3K27me3（组蛋白H3赖氨酸27三甲基化）通过复制复制的植物细胞通过组蛋白变体H3.1的DNA复制而得以恢复。植物进化出了一种在H3.1上进行有效K27三甲基化的机制，这对于从母细胞到子细胞继承沉默记忆至关重要。我们说明了这种机制如何在发育过渡到开花过程中建立H3K27me3介导的沉默。我们的研究揭示了一种机制，该机制负责通过细胞分裂在植物细胞中传递H3K27me3，从而使H3K27me3充当表观遗传标记。