Maimónides Biomedical Research Institute of Córdoba (IMIBIC), Av. Menéndez Pidal, 14004, Córdoba, Spain.
University of Córdoba, Campus de Rabanales, Edif. C5, 14071, Córdoba, Spain.
Plant J. 2017 Dec;92(6):1170-1181. doi: 10.1111/tpj.13753. Epub 2017 Nov 27.
By controlling gene expression, DNA methylation contributes to key regulatory processes during plant development. Genomic methylation patterns are dynamic and must be properly maintained and/or re-established upon DNA replication and active removal, and therefore require sophisticated control mechanisms. Here we identify direct interplay between the DNA repair factor DNA damage-binding protein 2 (DDB2) and the ROS1-mediated active DNA demethylation pathway in Arabidopsis thaliana. We show that DDB2 forms a complex with ROS1 and AGO4 and that they act at the ROS1 locus to modulate levels of DNA methylation and therefore ROS1 expression. We found that DDB2 represses enzymatic activity of ROS1. DNA demethylation intermediates generated by ROS1 are processed by the DNA 3'-phosphatase ZDP and the apurinic/apyrimidinic endonuclease APE1L, and we also show that DDB2 interacts with both enzymes and stimulates their activities. Taken together, our results indicate that DDB2 acts as a critical regulator of ROS1-mediated active DNA demethylation.
通过控制基因表达，DNA 甲基化有助于植物发育过程中的关键调控过程。基因组甲基化模式是动态的，必须在 DNA 复制和主动去除时得到正确的维持和/或重建，因此需要复杂的控制机制。在这里，我们鉴定了 DNA 修复因子 DNA 损伤结合蛋白 2（DDB2）与 ROS1 介导的活性 DNA 去甲基化途径在拟南芥中的直接相互作用。我们表明 DDB2 与 ROS1 和 AGO4 形成复合物，并且它们在 ROS1 基因座上发挥作用，以调节 DNA 甲基化水平，从而调节 ROS1 表达。我们发现 DDB2 抑制 ROS1 的酶活性。ROS1 产生的 DNA 去甲基化中间体由 DNA 3'-磷酸酶 ZDP 和无嘌呤/无嘧啶内切核酸酶 APE1L 处理，我们还表明 DDB2 与这两种酶相互作用并刺激它们的活性。总之，我们的结果表明 DDB2 是 ROS1 介导的活性 DNA 去甲基化的关键调节剂。
