National Key Laboratory of Plant Molecular Genetics and Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, The Chinese Academy of Sciences, Shanghai, 201602, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
J Integr Plant Biol. 2021 Jun;63(6):1091-1096. doi: 10.1111/jipb.13103. Epub 2021 Jun 3.
RNA-directed DNA methylation (RdDM) is a plant-specific de novo DNA methylation pathway, which has extensive cross-talk with histone modifications. Here, we report that the maize RdDM regulator SAWADEE HOMEODOMAIN HOMOLOG 2 (SHH2) is an H3K9me1 reader. Our structural studies reveal that H3K9me1 recognition is achieved by recognition of the methyl group via a classic aromatic cage and hydrogen-bonding and salt-bridge interactions with the free protons of the mono-methyllysine. The di- and tri-methylation states disrupt the polar interactions, decreasing the binding affinity. Our study reveals a mono-methyllysine recognition mechanism which potentially links RdDM to H3K9me1 in maize.
RNA 指导的 DNA 甲基化（RdDM）是一种植物特有的从头 DNA 甲基化途径，它与组蛋白修饰有广泛的交叉对话。在这里，我们报告说，玉米 RdDM 调节因子 SAWADEE HOMEODOMAIN HOMOLOG 2（SHH2）是一种 H3K9me1 阅读器。我们的结构研究表明，H3K9me1 的识别是通过经典的芳香笼通过识别甲基基团来实现的，并且通过与单甲基赖氨酸的游离质子形成氢键和盐桥相互作用来实现。二甲基化和三甲基化状态破坏了极性相互作用，降低了结合亲和力。我们的研究揭示了一种单甲基赖氨酸识别机制，它可能将 RdDM 与玉米中的 H3K9me1 联系起来。
