Role of the intrinsically disordered protein PIR in Polycomb silencing and environmental responses in Arabidopsis

该项目的目标是揭示植物在干旱等恶劣条件下生存的分子基础。 当植物经历干旱期时，基因组中的基因子集被称为Polycomb的蛋白质调节剂关闭或沉默。这种沉默有助于植物保存重要的资源，以度过干旱。Polycomb如何沉默基因的某些方面已经被理解，但Polycomb如何在干旱中沉默正确的基因仍然是一个谜。根据最近研究获得的线索，该项目将研究一种新发现的称为PIR的蛋白质，它可能提供干旱和Polycomb行动之间缺失的联系。了解这种联系可能会对农业产生广泛的影响，因为这些发现将有助于植物育种者开发出在干旱环境中生长得更好的作物品种。该项目还将通过改善课堂环境中的结构化主动学习活动，在入门和高级生物课程中产生教育影响。 此外，我们将开发和传播研究实验室模块，让高中生参与真实的研究经验。这些教育活动旨在提高不同学生群体在科学领域的成功率和保留率，并有望为未来STEM劳动力的准备做出贡献。在植物和动物中，Polycomb蛋白复合物长期以来被认为是关键的发育调节剂，并且对它们如何通过组蛋白修饰和染色质压实来抑制基因表达有很多了解。与此相反，很少有人了解这些调节器如何控制基因表达，以响应外源性线索。 该项目将使用模式植物拟南芥来研究干旱胁迫如何通过Polycomb Repressive Complex 2（PRC 2）与另一种称为Polycomb Interacting Repressor（PIR）的蛋白质的相互作用来影响沉默。初步结果提供的证据表明，PIR与干旱胁迫反应有关，并且它与PRC 2在遗传和物理上相互作用。 这些观察结果将被跟踪，以探讨：干旱胁迫如何影响招聘和活性的PIR/PRC 2复合物染色质; PIR是否作为一个非化学计量辅助PRC 2组件的功能;以及干旱是否导致PIR，这是一个内在的无序蛋白质，形成无膜相分离的核凝聚物，称为polycomb体。 总之，这些结果应该提供干旱反应和基于染色质的调节之间的新的机制联系。该奖项由遗传机制计划共同资助。（分子和细胞生物科学部）和植物基因组研究计划以及生理机制和生物力学计划（综合有机系统部），该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响进行评估，被认为值得支持审查标准。

The goal of this project is to uncover the molecular basis for plant survival under harsh conditions, such as drought. When plants experience a dry spell, subsets of genes in the genome are turned off, or silenced, by a protein regulator called Polycomb. This silencing helps the plant conserve crucial resources to survive the drought. Some aspects of how Polycomb works to silence genes is understood, but exactly how Polycomb targets the correct genes to silence in response to drought is still a mystery. Following up on clues obtained from recent studies, this project will study a newly identified protein called PIR, which may provide the missing link between drought and Polycomb action. Understanding this connection could have broad impacts for agriculture, as the findings would help plant breeders develop crop varieties that can grow better in dry environments. The project will also have educational impact by improving structured active learning activities in classroom settings, in both introductory and advanced biology courses. In addition, we will develop and disseminate research laboratory modules for engaging high school students in authentic research experiences. The educational activities are aimed at enhancing the success and retention of diverse groups of students in science and are expected to contribute to preparation of a future STEM workforce.In plants and animals, Polycomb protein complexes have long been recognized as key developmental regulators and much is known about how they repress gene expression by histone modification and chromatin compaction. In contrast, less is understood about how these regulators control gene expression in response to exogenous cues. This project will use the model plant Arabidopsis thaliana to study how drought stress influences silencing through interaction of the Polycomb Repressive Complex 2 (PRC2) with another protein, called Polycomb Interacting Repressor (PIR). Preliminary results provided evidence that PIR is linked to drought stress response and that it interacts genetically and physically with PRC2. These observations will be followed up to explore: how drought stress influences recruitment and activity of PIR/PRC2 complexes on chromatin; whether PIR functions as a non-stoichiometric auxiliary PRC2 component; and whether drought leads PIR, which is an intrinsically disordered protein, to form membrane-less phase-separated nuclear condensates, known as polycomb bodies. Together, the results should provide new mechanistic links between drought response and chromatin-based regulation. This award was co-funded by the Genetic Mechanisms Program (Division of Molecular and Cellular Biosciences) and by the Plant Genome Research Program and the Physiological Mechanisms and Biomechanics Program (Division of Integrative Organismal Systems), all in the Directorate for Biological Sciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.