Dissecting the Relationship between a CHD3 Chromatin Remodeler and the Repressive Epigenetic Mark H3K27me3 in Arabidopsis

智力优势：该项目的长期目标是了解CHD 3类ATP依赖性染色质重塑因子如何有助于调节基因表达和发育特征。 在动物模型系统中，CHD 3蛋白已被证明通过多亚基复合物（Mi-2/NuRD）与组蛋白脱乙酰酶组合来抑制在分化和发育中起关键作用的基因的转录。 在植物模式系统拟南芥中，CHD 3基因PICKLE也抑制基因的表达，并在发育转换中起重要作用。 然而，动物中PICKLE功能和CHD 3功能之间存在两个关键差异。 首先，PICKLE似乎在Mi-2/NuRD的植物等效物中不起作用。 第二，PICKLE似乎通过形成抑制性染色质标记，即组蛋白H3赖氨酸27（H3 K27 me 3）的三甲基化来起作用。 已知这种组蛋白修饰在动物和植物的基因抑制中起关键作用，但在动物中不受CHD 3蛋白的直接调节。为了了解PICKLE如何调节基因表达，该项目将利用强大的遗传，生物化学和发育工具来探索CHD 3蛋白如何有助于染色质结构和基因表达。 具体而言，实验旨在表征重组PICKLE蛋白的重塑活性，并检查各种保守蛋白结构域对体外和体内PICKLE功能的贡献。 结果将阐明新的机制，预计将普遍适用于所有真核生物CHD 3改造的行动。更广泛的影响：计划的研究与NSF的教育使命。 该项目将建立在让学生参与研究的悠久传统之上，为本科生和研究生提供开展研究的机会。 这将为学生提供与染色质生物学，模型系统和基于基因组的方法相关的科学基础。 最后，PI将继续将他在实验室的经验与课堂上的经验相结合，从而为学生提供更有意义的教育体验。

Intellectual Merit: The long-term objective of this project is to understand how the CHD3 class of ATP-dependent chromatin remodeling factors contributes to regulation of gene expression and developmental identity. In animal model systems, CHD3 proteins have been shown to act through a multisubunit complex (Mi-2/NuRD) in combination with histone deacetylase to repress transcription of genes that play a critical role in differentiation and development. In the plant model system Arabidopsis thaliana, the CHD3 gene, PICKLE, also represses expression of genes and plays an important role in developmental transitions. However, there are two key differences between PICKLE function and CHD3 function in animals. First, PICKLE does not appear to function in the plant equivalent of Mi-2/NuRD. Second, PICKLE appears to operate through formation of the repressive chromatin mark, trimethylation of histone H3 lysine 27 (H3K27me3). This histone modification is known to play a critical role in gene repression in both animals and plants, but is not directly regulated by CHD3 proteins in animals. To understand how PICKLE regulates gene expression, this project will take advantage of powerful genetic, biochemical, and developmental tools to explore how CHD3 proteins contribute to chromatin structure and gene expression. Specifically, experiments will be aimed at characterizing the remodeling activity of recombinant PICKLE protein and examining the contribution of various conserved protein domains to PICKLE function in vitro and in vivo. The results will shed light on new mechanisms of action for CHD3 remodelers that are anticipated to be generally applicable to all eukaryotes.Broader Impacts: The planned research aligns well with the education mission of NSF. The project will build on a long tradition of engaging students in research by providing both undergraduates and graduate students with opportunities to carry out research. This will provide the students with a solid foundation in science associated with chromatin biology, model systems, and genome-based approaches. Finally, the PI will continue to synergize his experiences in the lab with those in the classroom and thereby provide a more meaningful educational experience to students.