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

智力优点。 生物系统对遗传和环境扰动非常稳健。先前的研究发现分子伴侣 HSP90 是维持表型鲁棒性的重要机制。 HSP90 扰动会降低稳健性并揭示植物、果蝇、鱼类和酵母中隐藏的遗传变异。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。现在已在拟南芥中鉴定出另一种假定的表型变异新型电容器：RNA 聚合酶 V。与 HSP90 一样，Pol V 保持了表型稳健性。 HSP90 主要在蛋白质折叠中发挥作用，而 Pol V 则在 RNA 指导的 DNA 甲基化、沉默转座子、串联重复和基因间区域中发挥作用，并驱动 rDNA 的压缩。作为真正的电容器，功能性 Pol V 应隐藏遗传变异。在目标 1 中，将使用一种创新方法来测试功能性 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，因此 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。如果属实，选择应该修复这些表型。在目标 2 中，将通过繁殖具有极长和极短茎的野生型和 pol V 突变体的个体幼苗来进行选择实验，然后记录一系列表型以确定选择反应。 在目标 3 中，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 HSP90 和 Pol V 之间的机制重叠程度。 Pol V 作为一种功能独特的电容器的拟议表征首次提供了识别与鲁棒性下降相关的常见分子特征的机会，无论是作为原因还是后果。该项目旨在将 Pol V 建立为拟南芥中的新型电容器，解决了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在共同分子特征（在本例中是在染色质）上收敛的假设而开辟了新天地。更广泛的影响。该项目为研究生和本科生提供学生培训机会。 代表性不足的少数族裔学生将通过 PI 开发和运行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师合作将使华盛顿大学基因组科学教师能够访问少数族裔服务机构并回访西雅图。这些访问旨在扩大教师及其研究生（他们将成为明天的教师）的研究视野。

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.