EAGER: DNA demethylation in maize pollen gene regulation

花粉由两种类型的细胞组成，即精子细胞和花粉营养细胞，每种细胞都有不同的活性基因。花粉营养细胞携带体内的精子细胞，首先通过空气，然后通过雌性生殖结构与卵子融合并产生种子。在这个过程中，花粉营养细胞使用大量的基因来生长和发育，并保护它们的精细胞。能够在恶劣的环境条件下生存的健壮的花粉对于玉米(玉米)等作物的高产至关重要。特别是在耐热性方面，花粉是作物改良的重要考虑因素。最近的发现表明，被称为DNA糖基酶的酶可以改变DNA的结构，对于激活花粉营养细胞中的基因是重要的。本项目旨在研究这些酶在玉米花粉中的功能。这些结果将产生关于花粉遗传学的新知识，以及将这些知识用于植物繁殖的新工具。DNA甲基化通常会抑制重复的DNA。然而，在某些情况下，DNA甲基化可以调节发育基因的表达。在植物中，DNA糖基酶可以消除甲基化，并可以调节表观遗传。该项目的目标是确定去甲基化的基因和基因组的基因间隔区，并确定去甲基化在花粉中的功能意义。这将涉及一种新的方法来确定在单细胞分辨率下去甲基化对正常和糖基酶缺陷花粉混合群体中基因表达的影响。该项目的顶峰将是测试工程糖基酶使特定遗传元素去甲基化的潜力。这将是朝着创造实验资源的更大目标迈出的第一步，该资源用于研究甲基化的后果以及研究花粉中的表观遗传控制基因表达，并有可能遗传到下一代。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Pollen is made of two cell types, sperm cells and pollen vegetative cells, each with different sets of active genes. Pollen vegetative cells carry the sperm cells inside them on their journey first through the air and then through the female reproductive structure to fuse with eggs and make seeds. During this process, the pollen vegetative cells use a large number of genes to grow and develop and to protect their cargo of sperm cells. Robust pollen that can survive adverse environmental conditions is essential for high yield in crops like corn (maize). Especially in regard to heat tolerance, pollen is an important consideration in crop improvement. Recent discoveries have revealed that enzymes called DNA glycosylases, which change the structure of DNA, are important for activating genes in pollen vegetative cells. This project aims to investigate the function of these enzymes in corn pollen. The results will yield new knowledge about pollen genetics and new tools for putting that knowledge to use in plant reproduction.DNA methylation generally represses repetitive DNA. In certain situations, however, DNA methylation can regulate developmental gene expression. In plants, DNA glycosylases remove methylation and can mediate epigenetic inheritance. The goal of this project is to identify both genes and intergenic regions of the genome that are targeted for demethylation and to determine the functional significance of demethylation in pollen. This will involve a novel approach to determine the effects of demethylation on gene expression at single-cell resolution in mixed populations of normal and glycosylase-defective pollen. The capstone of the project will be testing the potential of engineering glycosylases to demethylate specific genetic elements. This will be an initial step toward a larger goal of creating experimental resources for studying the consequences of methylation as well as for epigenetically controlling gene expression in pollen, with potential for heritability into the next generation.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.