Coupling of H3K27me3 recognition with transcriptional repression through the BAH-PHD-CPL2 complex in Arabidopsis.
Coupling of H3K27me3 recognition with transcriptional repression through the BAH-PHD-CPL2 complex in Arabidopsis.
复制标题
拟南芥中通过 BAH-PHD-CPL2 复合物将 H3K27me3 识别与转录抑制耦合。
DOI：
10.1038/s41467-020-20089-0
复制
发表时间：
2020-12-04
影响因子：
16.6
通讯作者：
Duan CG
中科院分区：
文献类型：
--
作者：
Zhang YZ;Yuan J;Zhang L;Chen C;Wang Y;Zhang G;Peng L;Xie SS;Jiang J;Zhu JK;Du J;Duan CG
组蛋白3赖氨酸27三甲基化（H3K27me3）介导的表观遗传沉默在多个生物学过程中起着关键作用。然而，对于H3K27me3的识别和转录抑制机制，人们仅了解一部分。在此，我们报道一种H3K27me3识别和转录抑制的机制。我们的结构和生化数据表明，在拟南芥中，BAH结构域蛋白AIPP3以及PHD蛋白AIPP2和PAIPP2分别协同识别H3K27me3和未修饰的H3K4组蛋白标记。BAH - PHD二价组蛋白识别复合物使大量富含H3K27me3的基因座沉默，包括许多发育和应激反应相关基因，例如RNA沉默效应基因ARGONAUTE 5（AGO5）。我们发现BAH - PHD模块与CPL2（一种植物特异性的聚合酶II羧基末端结构域（CTD）磷酸酶）结合，形成用于转录抑制的BAH - PHD - CPL2复合物（BPC）。BPC复合物通过CPL2介导的CTD去磷酸化抑制转录，从而抑制聚合酶II从转录起始位点释放。我们的工作揭示了一种通过改变聚合酶II磷酸化状态将H3K27me3识别与转录抑制相耦合的机制，从而有助于我们理解依赖于H3K27me3的沉默机制。
组蛋白3赖氨酸27三甲基化（H3K27me3）介导基因表达的表观遗传沉默。在此，Zhang等人表明，在拟南芥中，具有BAH结构域的H3K27me3识别蛋白AIPP3与PHD蛋白以及植物特异性的聚合酶II磷酸酶CPL2形成复合物，通过去磷酸化抑制聚合酶II的活性。
Histone 3 Lys 27 trimethylation (H3K27me3)-mediated epigenetic silencing plays a critical role in multiple biological processes. However, the H3K27me3 recognition and transcriptional repression mechanisms are only partially understood. Here, we report a mechanism for H3K27me3 recognition and transcriptional repression. Our structural and biochemical data showed that the BAH domain protein AIPP3 and the PHD proteins AIPP2 and PAIPP2 cooperate to read H3K27me3 and unmodified H3K4 histone marks, respectively, in Arabidopsis. The BAH-PHD bivalent histone reader complex silences a substantial subset of H3K27me3-enriched loci, including a number of development and stress response-related genes such as the RNA silencing effector gene ARGONAUTE 5 (AGO5). We found that the BAH-PHD module associates with CPL2, a plant-specific Pol II carboxyl terminal domain (CTD) phosphatase, to form the BAH-PHD-CPL2 complex (BPC) for transcriptional repression. The BPC complex represses transcription through CPL2-mediated CTD dephosphorylation, thereby causing inhibition of Pol II release from the transcriptional start site. Our work reveals a mechanism coupling H3K27me3 recognition with transcriptional repression through the alteration of Pol II phosphorylation states, thereby contributing to our understanding of the mechanism of H3K27me3-dependent silencing. Histone 3 Lys 27 trimethylation (H3K27me3) mediates epigenetic silencing of gene expression. Here, Zhang et al. show that in Arabidopsis, the BAH-domain H3K27me3-reader protein AIPP3 forms a complex with PHD proteins and CPL2, a plant-specific Pol II phosphatase, to inhibit Pol II activity by dephosphorylation.