Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
Science. 2017 Sep 15;357(6356):1146-1149. doi: 10.1126/science.aan4965. Epub 2017 Aug 17.
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.
基因表达模式通过细胞周期的传播需要在 DNA 复制导致的两倍稀释后迅速恢复表观遗传标记。在这里，我们表明转录抑制标记 H3K27me3（组蛋白 H3 赖氨酸 27 三甲基化）通过与 DNA 复制偶联的组蛋白变体 H3.1 的修饰在复制的植物细胞中得到恢复。植物进化出一种在 H3.1 上进行高效 K27 三甲基化的机制，这对于从母细胞到子细胞沉默记忆的遗传至关重要。我们说明了这种机制如何在向开花的发育转变过程中建立 H3K27me3 介导的沉默。我们的研究揭示了一种通过细胞分裂在植物细胞中传递 H3K27me3 的机制，使 H3K27me3 能够作为一种表观遗传标记发挥作用。
