Prion domains in Plant Environmental Response

植物通过调整它们的发育来适应环境，以响应包括光和温度在内的线索。这使它们能够预测压力，通过其生长和发育的变化做出反应，并在不同的环境条件下优化其生存和繁殖成功。随着气候变化，成功适应的过程对许多物种来说都是一个挑战。由于气候变化，植物的物候已经发生了变化，但其潜在的机制还没有得到很好的理解。该联盟最近发现，控制生长，发育和应激反应的关键转录调节因子含有朊病毒样结构域（PrD）。PrD赋予响应环境信号而经历相变（液-液相分离，LLPS）的能力，使这些蛋白质能够充当发育开关。该项目的重点是PrD含有转录因子PLETHORA 3（PLT 3），热休克因子1a（HSFA 1a）和植物色素相互作用因子4，5和7（“PIF”）。这些转录因子在植物发育和胁迫反应中起主要调节作用，并且都具有PrD。我们已经证明，他们在体外和/或体内进行LLPS。使用一个集成的体外，结构，建模和体内的方法，我们将确定的变量是重要的LLPS，检查不同的氨基酸序列在相分离和设计突变体与改变LLPS的作用。通过迭代的体外表征，包括小角X射线和中子散射（SAXS/SANS），荧光显微镜和理论建模，使用粗粒模拟和原子模型的研究，我们的靶蛋白的LLPS的规则将被确定。这些在体外和建模的结果将与在模型植物，拟南芥中的瞬时表达系统和稳定转化系的体内研究。荧光标记的靶蛋白和突变体的体内成像、ChIP-seq研究和转录组分析将使我们能够将植物生物反应与我们蛋白质的LLPS特性直接联系起来。研究中的系统将允许在细胞和生物体水平上直接探测LLPS的影响。了解PrD如何控制蛋白质活性以响应物理化学环境将使我们能够直接调节植物的生长和胁迫反应。这将代表着我们对植物如何适应环境的理解的一个飞跃。这个跨学科项目结合了法国和德国合作伙伴在结构生物学，生物物理建模，体外分子测定和植物研究方面的专业知识。

Plants adapt to the environment by adjusting their development in response to cues including light and temperature. This enables them to anticipate stresses, respond via changes in their growth and development and optimize their survival and reproductive success under varying environmental conditions. With climate change, the process of successful adaptation represents a challenge for many species. The phenology of plants has already altered due to climate change, but the underlying mechanisms of this are not well understood. The consortium has recently discovered that key transcriptional regulators controlling growth, development and stress response contain prion-like domains (PrDs). PrDs confer the ability to undergo phase-change (liquid-liquid phase separation, LLPS) in response to environmental signals, enabling these proteins to act as developmental switches. The project focuses on the PrD containing transcription factors PLETHORA 3 (PLT3), HEAT SHOCK FACTORA1a (HSFA1a) and the PHYTOCHOROME INTERACTING FACTORS 4,5 and 7 (“PIFs”). These transcription factors act as master regulators in plant development and stress response and all possess PrDs. We have demonstrated that they undergo LLPS in vitro and/or in vivo. Using an integrated in vitro, structural, modeling and in vivo approach, we will determine the variables that are important for LLPS, examine the role of different amino acid sequences in phase separation and design mutants with altered LLPS. Through iterative in vitro characterization including studies by small angle X-ray and neutron scattering (SAXS/SANS), fluorescence microscopy and theoretical modeling using course grained simulations and atomistic models, the rules governing LLPS of our target proteins will be determined. These in vitro and modeling results will be correlated with in vivo studies in transient expression systems and stably transformed lines in the model plant, Arabidopsis thaliana. In vivo imaging of fluorescently labelled target proteins and mutants, ChIP-seq studies and transcriptome analysis will allow us to directly relate plant biological response to the LLPS properties of our proteins. The system under study will allow the direct probing of the effects of LLPS at the cellular and organism level. Understanding how PrDs control protein activity in response to the physicochemical environment will enable us to directly tune growth and stress responses in plants. This will represent a step-change in our understanding of how plants adapt to their environment. This interdisciplinary project combines expertise from French and German partners in structural biology, biophysical modeling, in vitro molecular assays, and in planta studies.