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

智力上的功绩。生物系统对遗传和环境扰动的耐受性非常强。以前的研究发现，伴侣HSP90是维持表型稳定性的重要机制。HSP90的干扰降低了稳健性，并揭示了植物、苍蝇、鱼类和酵母中隐秘的遗传变异。HSP90具有隐藏和释放遗传变异的特性，被称为表型变异的电容。另一种可能的表型变异的新电容现在已经在拟南芥中被发现：RNA聚合酶V。与HSP90一样，POLV也保持了表型的稳定性。HSP90主要作用于蛋白质折叠，而Pol V主要作用于RNA引导的DNA甲基化、沉默转座子、串联重复序列和基因间隔区，并驱动rDNA的紧凑。作为一个真正的电容器，功能性的POLV应该隐藏遗传变异。在目标1中，将使用一种创新的方法来测试功能性POLV是否隐藏遗传变异。由于PolV影响染色质状态和基因组稳定性，PolV突变体的表型变异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。如果为真，则选择应修复这些表型。在目标2中，将通过繁殖野生型和polV突变体的极长和极短茎的单个幼苗，然后记录一系列表型来确定选择反应，从而进行选择实验。在目标3中，将通过对Pol V和HSP90水平降低的植物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。建议将POL V描述为功能不同的电容器，首次提供了机会来确定与稳健性降低相关的共同分子特征，无论是原因还是后果。该项目旨在通过建立Pol V作为A.thaliana中的一种新的电容器来解决有争议的但基本的表型电容的概念。它开创性地测试了这样一个假设，即功能上不同的电容机制会聚在共同的分子特征上，在这种情况下是在染色质上。该项目为研究生和本科生提供了培训机会。代表不足的少数族裔学生将通过国际学生联合会制定和运营的正在进行的暑期实习计划参与学术研究。与新墨西哥大学和莫尔豪斯学院的教职员工合作将使华盛顿大学基因组科学学院的教职员工能够访问这两个为少数族裔服务的机构，并回访西雅图。这些访问的目的是扩大教师和他们的研究生的研究视野，他们将是明天的教师。

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.