EAGER: RNA Polymerase V as a Novel Capacitor of Phenotypic Variation in Arabidopsis thalian

知识价值。生物系统对遗传和环境扰动具有显著的鲁棒性。先前的研究发现伴侣蛋白HSP90是维持表型稳健性的重要机制。HSP90扰动降低了鲁棒性，揭示了植物、苍蝇、鱼和酵母的隐遗传变异。由于其隐藏和释放遗传变异的特性，HSP90被称为表型变异的电容器。在拟南芥中发现了另一个假定的表型变异的新电容器：RNA聚合酶V。与HSP90一样，Pol V保持表型稳健性。虽然HSP90主要在蛋白质折叠中起作用，但Pol V在rna导向的DNA甲基化，沉默转座子，串联重复序列和基因间区域中起作用，并驱动rDNA的压实。作为一个真正的电容器，功能性的Pol V应该隐藏遗传变异。在目标1中，一种创新的方法将用于测试功能性Pol V是否隐藏遗传变异。由于Pol V影响染色质状态和基因组稳定性，Pol V突变体表型变异的增加可能是由不同的、潜在可遗传的表观遗传或遗传状态引起的。如果这是真的，自然选择应该会固定这些表型。在目标2中，选择实验将通过繁殖具有极长和极短茎的野生型和pol V突变体的个体幼苗进行，然后记录一系列表型以确定选择反应。在Aim 3中，HSP90和Pol V之间的机制重叠程度将通过在Pol V和HSP90水平降低的植物中进行全基因组表达分析来评估。Pol V作为一种功能独特的电容器的特性，首次提供了识别与鲁棒性下降相关的共同分子特征的机会，无论是作为原因还是后果。本项目旨在通过在拟南草中建立Pol V作为一种新型电容器来解决有争议但基本的表型电容概念。它通过测试功能不同的电容机制会聚在共同的分子特征上的假设，在染色质的情况下，开辟了新的领域。更广泛的影响。该项目为研究生和本科生提供了培训机会。未被充分代表的少数族裔学生将通过PI开发和运营的暑期实习项目参与学术研究。与新墨西哥大学和莫尔豪斯学院的教员合作，将使华盛顿大学基因组科学学院的教员能够访问少数民族服务机构并返回西雅图。这些访问旨在扩大教师及其研究生的研究视野，他们将成为未来的教师。

Intellectual Merit. Biological systems are remarkably robust to genetic and environmental perturbations. Previous research identified the chaperone HSP90 as an important mechanism in maintaining phenotypic robustness. HSP90 perturbation decreases robustness and reveals cryptic genetic variation in plants, flies, fish, and yeast. Due to its property of concealing and releasing genetic variation, HSP90 has been named a capacitor of phenotypic variation. Another putative novel capacitor of phenotypic variation has now been identified in Arabidopsis thaliana: RNA polymerase V. Like HSP90, Pol V maintains phenotypic robustness. Whereas HSP90 functions primarily in protein folding, Pol V functions in RNA-directed DNA methylation, silencing transposons, tandem repeats, and intergenic regions, and drives compaction of rDNA. As a bona fide capacitor, functional Pol V should conceal genetic variation. In Aim 1, an innovative approach will be used to test whether functional Pol V conceals genetic variation. As Pol V affects chromatin states and genome stability, the increased phenotypic variation in pol V mutants may be caused by different, potentially heritable epigenetic or genetic states. If true, selection should fix these phenotypes. In Aim 2, selection experiments will be conducted by propagating individual seedlings with extremely long and short stems for wild-type and pol V mutants and then documenting a range of phenotypes to determine the selection response. In Aim 3, the extent of mechanistic overlap between HSP90 and Pol V, will be assessed by conducting a whole-genome expression analysis in plants with reduced levels of Pol V and HSP90. The proposed characterization of Pol V as a functionally distinct capacitor offers, for the first time, the opportunity to identify common molecular features that are associated with decreased robustness, either as causes or consequences. This project addresses the controversial, yet fundamental, concept of phenotypic capacitance by aiming to establish Pol V as a novel capacitor in A. thaliana. It breaks new ground by testing the hypothesis that functionally distinct capacitance mechanisms converge at common molecular features, in this case at chromatin.Broader Impacts. The project offers opportunities for student training at both graduate and undergraduate levels. Underrepresented minority students will participate in academic research, through an ongoing summer internship program developed and run by the PI. Collaborations with faculty at the University of New Mexico and Morehouse College will enable visits of University of Washington Genome Sciences faculty to both minority serving institutions and return visits to Seattle. These visits are aimed at expanding research horizons for both faculty and their graduate students, who will be tomorrow's faculty members.