Tsuchiya Tokuji, Eulgem Thomas
a Institute for Integrative Genome Biology; Center for Plant Cell Biology; Department of Botany and Plant Sciences; University of California at Riverside; Riverside, CA USA.
Plant Signal Behav. 2014;9(7):e29202. doi: 10.4161/psb.29202.
Recently we reported that the Arabidopsis thaliana PHD-finger protein EDM2 (enhanced downy mildew 2) impacts disease resistance by affecting levels of di-methylated lysine 9 of histone H3 (H3K9me2) at an alternative polyadenylation site in the immune receptor gene RPP7. EDM2-dependent modulation of this post-translational histone modification (PHM) shifts the balance between full-length RPP7 transcripts and prematurely polyadenylated transcripts, which do not encode the RPP7 protein. Our previous work genetically linked, for the first time, PHMs to alternative polyadenylation and established EDM2 as a critical component mediating PHM-dependent polyadenylation control. However, how EDM2 is recruited to its genomic target sites and how it affects H3K9me2 levels is unknown. Here we show the PHD-finger module of EDM2 to recognize histone H3 bearing certain combinations of 3 distinct PHMs. Our results suggest that targeting of EDM2 to specific genomic regions is mediated by the histone-binding selectivity of its PHD-finger domain.
最近我们报道，拟南芥中的植物同源结构域（PHD）指蛋白EDM2（增强霜霉病2）通过影响免疫受体基因RPP7中一个可变聚腺苷酸化位点处组蛋白H3赖氨酸9二甲基化（H3K9me2）的水平来影响抗病性。这种翻译后组蛋白修饰（PHM）的EDM2依赖性调控改变了全长RPP7转录本与过早聚腺苷酸化转录本之间的平衡，而过早聚腺苷酸化转录本不编码RPP7蛋白。我们之前的研究首次从遗传学角度将PHM与可变聚腺苷酸化联系起来，并确定EDM2是介导PHM依赖性聚腺苷酸化控制的关键成分。然而，EDM2如何被招募到其基因组靶位点以及它如何影响H3K9me2水平尚不清楚。在这里，我们展示了EDM2的PHD指模块能够识别带有3种不同PHM特定组合的组蛋白H3。我们的结果表明，EDM2靶向特定基因组区域是由其PHD指结构域的组蛋白结合选择性介导的。
