Role of chromatin remodeling in gene regulation during maize basal endosperm development

玉米粒是食品、饲料、生物燃料、淀粉/糖和许多食品中的成分的全球来源。玉米籽粒的胚乳是营养物质的主要储存库。它由几个支持内核开发的功能独特的单元层组成。本项目研究了胚乳基底传递细胞（BETC）发育的分子和生理过程。特别是，实验将表征三羧酸（TCA）循环代谢物的作用，以及它们的副产物，作为染色质结构和基因表达的重要决定因素。包装成常染色质（开放染色质）通常会导致基因表达增加，而包装成异染色质（封闭染色质）通常是基因沉默的标志，代谢物在调节这种包装中的直接作用是一个新发现。该项目还将组织玉米基因沉默暑期实习（CornSInGS），为当地高中生提供实验室和田间实践，以学习作物性状的遗传。植物表型将用于证明基因沉默开关。该项目还将与弗吉尼亚州立大学的教师和本科生合作，进行与CornSInGS研讨会重叠的本科生暑期实习。研究结果将提供胚乳和健康玉米籽粒发育所需的细胞核生物过程的知识。基部胚乳传递细胞位于韧皮部末端的交界处，连接着光合产物的来源（叶片）和淀粉胚乳的贮藏细胞（库）。早期籽粒发育事件的核心是细胞过程，包括DNA复制、转录和RNA剪接。任何这些基本过程的错误调节都会导致细胞分化、生长和发育的缺陷。玉米ufo 1（Zmufo 1;橙色不稳定因子1）突变体具有BETC缺陷，其被发现与TCA循环基因、代谢物、活性氧（ROS）和基本调节过程的异常表达相关。因此，Zmufo 1突变体提供了一组不同的籽粒缺陷和植物表型，以帮助表征细胞分化。该建议将描述在早期基部胚乳发育过程中维持细胞稳态所需的代谢和表观遗传调控事件。具体目标是：1。表征BETC分化过程中由Zmufo 1调节的氧化还原依赖性时空染色质重塑。2.表征ZmUFO 1相关的蛋白质-蛋白质相互作用。3.确认预测的ZmUFO 1的ASF 1-组蛋白伴侣结构域的功能。从这个项目中获得的知识可以应用于了解支持其他具有经济重要性的谷物的胚和胚乳的其他特化细胞的发育。这个奖项反映了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审查标准进行评估，被认为值得支持。

Maize kernels are a global source of food, feed, biofuel, starches/sugars, and ingredients in many food products. The endosperm of the maize kernel is a primary reservoir of nutrients. It is composed of several functionally unique cell layers that support kernel development. This project investigates molecular and physiological processes of development in one such layer, the basal endosperm transfer cells (BETCs). In particular, experiments will characterize the role of tricarboxylic acid (TCA) cycle metabolites, as well as their byproducts, as important determinants of chromatin structure and gene expression. Packaging into euchromatin (open chromatin) often leads to increased gene expression, whereas packaging into heterochromatin (closed chromatin) is generally a marker of gene silencing, and the direct role for metabolites in regulating this packaging is a novel finding. The project will also organize Corn Summer Internships in Gene Silencing (CornSInGS) for hands-on laboratory and field exercises for local high school students to learn the inheritance of crop traits. Plant phenotypes will be used to demonstrate gene silencing switches. This project will also collaborate with faculty and undergraduates from Virginia State University for undergraduate summer internships overlapping with the CornSInGS workshop. Findings will provide knowledge of the biological processes in the nucleus that are required for the development of endosperm and a healthy maize kernel. Basal endosperm transfer cells lie at the interface of phloem termini connecting the source of photosynthates (leaves) with the storage cells (sink) of starchy endosperm. At the heart of early kernel developmental events are cellular processes, including DNA replication, transcription, and RNA splicing. Mis-regulation of any of these basic processes causes defects in cell differentiation, growth, and development. Maize ufo1 (Zmufo1; unstable factor for orange1) mutants have BETC defects that were found to be associated with aberrant expression of TCA cycle genes, metabolites, reactive oxygen species (ROS), and basic regulatory processes. Zmufo1 mutants therefore provide a varied set of kernel defects and plant phenotypes to help characterize cellular differentiation. This proposal will characterize metabolic and epigenetic regulatory events that are required to maintain cellular homeostasis during early basal endosperm development. Specific aims are: 1. Characterize redox-dependent, spatiotemporal chromatin remodeling during BETC differentiation as modulated by Zmufo1. 2. Characterize ZmUFO1-associated, protein-protein interactions. 3. Confirm functionality of the predicted ASF1-histone chaperone domain of ZmUFO1. The knowledge gained from this project can be applied to understand the development of other specialized cells supporting the embryo and endosperm of other cereal grains of economic importance.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.