A DREAM of NAC - Molecular mechanism of transcriptional adaptation to DNA stress

植物反复受到环境胁迫。一种特别有害的条件是酸性土壤，在世界许多地区，包括欧洲大部分地区以及许多发展中国家普遍存在。在pH低于5.5时，铝（Al）（地壳中最丰富的金属）以Al 3+离子的形式变得移动的并引起植物毒性。在ERA-CAPS项目的框架下，双方的前期工作主要集中在最近发现的铝对DNA的损伤效应，以拟南芥和大麦（一种对铝高度敏感的作物）为模型植物。与此同时，已经鉴定出拟南芥突变体，其在轻度DNA损伤条件下表现出比野生型更好的根生长，这一性状与作物高度相关。这些突变体之一是缺陷的NAC转录因子，一个密切的同源物的中央DNA损伤调节器SOG 1。另一个是转录因子MYB 3R 3的突变体，它已被证明是一种称为DREAM的阻遏物复合物的一部分。DREAM复合物是动物细胞周期控制的关键，由于其参与癌症，因此是当前研究的焦点。虽然在拟南芥中发现了DREAM复合体的组分，在发育和生理学中具有重要作用，但有关植物DREAM复合体的知识仍处于起步阶段，甚至该复合体的核心组成也尚不清楚。在我们的准备工作中，我们现在发现了上述NAC和梦想情结之间的联系。一个串联的亲和纯化实验使用的中央细胞周期调节器RBR 1的拟南芥作为诱饵，导致在鉴定这NAC转录因子，以及同源物的几乎所有成分的人的梦想复合物旁边的几个新的组件。在上一个项目奠定了坚实的基础之后，双方希望在贝多芬生命计划的框架内扩大合作，并开展长期合作，探索一种新的转录机制，描述植物如何调整其生长和生理学以适应遗传毒性环境条件。该项目的总体目标不仅是获得对DREAM复合物功能的基本和机制见解，而且还为这些结果的后续转化奠定基础，即产生抗Al作物。

Plants are repeatedly subjected to environmental stresses. A particular harmful condition is acidic soil, prevalent in many regions of the world including most parts of Europe as well as many developing countries. Below a pH of 5.5, Aluminium (Al), the most abundant metal in the crust of the earth, becomes mobile in the form of Al3+ ions and causes phytotoxicity. Previous work of both partners in the frame of an ERA-CAPS project has focused on a recently discovered DNA damaging effect of Al using Arabidopsis and barley, a crop that is highly sensitive to Al, as model plants.In parallel, Arabidopsis mutants have been identified, that show better root growth than the wildtype under mildly DNA damaging conditions, a trait highly relevant to be translated to crops. One of these mutants is defective in a NAC transcription factor, a close homolog of the central DNA damage regulator SOG1. Another one is mutant for the transcription factor MYB3R3, which has been shown to be part of a repressor complex called DREAM. The DREAM complex is key for cell cycle control in animals and is in the focus of current research due to its involvement in cancer. Although components of a DREAM complex have been discovered in Arabidopsis with important roles in development and physiology, knowledge about the plant DREAM complex is in its infancy and even the core composition of the complex is not yet clear. In our preparatory work, we have now discovered a link between the above-mentioned NAC and the DREAM complex. A tandem affinity purification experiment using the central cell cycle regulator RBR1 of Arabidopsis as a bait resulted in the identification of this NAC transcription factor as well as homologs of almost all constituents of the human DREAM complex next to several new components. Following the solid base that was laid in the previous project, both partners want to expand their collaboration now in the frame of the Beethoven Life program and develop a long-term collaboration exploring a novel transcriptional mechanism describing how plants adjust their growth and physiology to genotoxic environmental conditions. The overall aim of this project is not only to obtain fundamental and mechanistic insights into the function of the DREAM complex but also to build a foundation for the subsequent translation of these results, i.e. the generation of Al resistant crops.