Gene Imprinting Networks in Arabidopsis

印迹基因的等位基因表现不同，取决于它们是遗传自父本还是母本。印记调节了哺乳动物和开花植物（被子植物）正常发育所必需的一些基因。在哺乳动物中，印迹基因有助于控制胎儿生长和胎盘发育。胚乳是被子植物双受精的产物之一，是植物印迹的重要部位。胚乳具有类似于胎盘的功能，支持种子的生长发育。某些基因印记的失败导致胚胎流产和种子死亡。遗传和分子研究表明，表观遗传调控，特别是亲本特异性基因表达（基因组印记），在胚乳发育中起着重要作用，影响种子的大小和质量。模式植物拟南芥被用来研究基因印记是如何被表观遗传调控的。表观遗传信息存在于染色质、DNA及其相关蛋白中，以开放的构象存在于转录因子可接近的基因中，或以封闭的构象存在于沉默的基因中。两个相互依赖的过程调节染色质构象：Polycomb组蛋白甲基化DNA包裹的组蛋白，以及DME DNA糖基化酶去甲基化DNA。在拟南芥中，DME DNA去甲基化酶和Polycomb组蛋白（MEA, FIS2）是基因印迹的主要调控因子。然而，这些蛋白的作用位点很少，只有少数的印迹基因被确定。本项目将采用高效的基因组技术，系统地阐明拟南芥胚乳的印迹基因网络。具体而言，本研究将识别所有印迹基因，区分所有被二甲醚去甲基化的印迹基因，定义Polycomb组蛋白调控的印迹基因，并对印迹基因进行功能分析。这些研究将有助于对被子植物基因印迹的调控和功能有更全面的认识。更广泛的影响：这项研究将促进对胚乳的了解，胚乳是作物种子的主要组成部分，也是蛋白质、淀粉和脂质营养物质的合成和储存场所，构成了世界粮食供应的一半。印迹基因通过控制资源分配到胚乳来影响种子产量。了解这一重要过程将使新技术能够提高作物产量和粮食产量，以养活不断增长的人口，并解决我们社会中的饥饿问题。由于这项研究将遗传学与基因组学和计算分析相结合，参与的学生将获得宝贵的跨学科培训，使他们能够解决未来需要多方面方法的问题。此外，通过与旨在促进生物科学中代表性不足的群体的本科生成功的项目合作，以及将研究成果和最先进的基因组学和计算方法纳入植物生物学讲座和实验室课程，将对本科生的科学教学整合到研究活动中。

Alleles of imprinted genes are expressed differently depending on whether they are inherited from the male or female parent. Imprinting regulates a number of genes essential for normal development in mammals and flowering plants (angiosperms). In mammals, imprinted genes contribute to the control of fetal growth and placental development. The endosperm, one of the products of angiosperm double fertilization, is an important site of imprinting in plants. The endosperm has functions analogous to the placenta and supports seed growth and development. Failure to imprint certain genes results in embryo abortion and seed death. Genetic and molecular studies have shown that epigenetic regulation, particularly parent-specific gene expression (genomic imprinting), plays an essential role in endosperm development, influencing seed size and quality. The model plant Arabidopsis is being used to study how gene imprinting is epigenetically regulated. Epigenetic information resides in chromatin, DNA and its associated proteins, which exists in an open conformation with the genes accessible to transcription factors or in a compacted conformation that silences genes. Two interdependent processes regulate chromatin conformation: Polycomb group proteins methylate histone proteins around which the DNA is wrapped, and the DME DNA glycosylase demethylates DNA. In Arabidopsis, the DME DNA demethylase and Polycomb group proteins (MEA, FIS2) are the primary regulators of gene imprinting. However, very few sites of action of these proteins, and only a handful of imprinted genes, have been identified. This project will implement highly efficient genomic technologies to systematically elucidate the network of imprinted genes in Arabidopsis endosperm. Specifically, the research will identify all imprinted genes, distinguish all imprinted genes demethylated by DME, define imprinted genes regulated by Polycomb group proteins, and functionally analyze imprinted genes. These studies will lead to a comprehensive understanding of the regulation and function of gene imprinting in angiosperms. Broader Impacts: This research will advance understanding of endosperm, a major component of crop seeds and the site of synthesis and storage of protein, starch, and lipid nutrients that comprise half of the world food supply. Imprinted genes influence seed yield by controlling resource allocation to the endosperm. Understanding this important process will enable new technologies that increase crop yield and food production to feed a growing population and to address the problem of hunger in our society. Because this research combines genetics with genomics and computational analysis, the students who participate will receive invaluable cross-disciplinary training that will enable them to address future questions that require a multifaceted approach. Moreover, the teaching of science to undergraduates will be integrated into the research activities through collaboration with programs designed to promote the success of undergraduate students from groups underrepresented in the biological sciences and by incorporating research results and state-of-the-art genomic and computational approaches into plant biology lecture and laboratory classes.