蓖麻基因组印迹的表观调控机制研究

项目名称： 蓖麻基因组印迹的表观调控机制研究

项目编号： No.31501034

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 生物科学

项目作者： 董雪

作者单位： 中国科学院昆明植物研究所

项目金额： 20万元

中文摘要： 基因组印迹是一种不符合孟德尔规律的遗传现象，主要发生在动物的胎盘和植物的胚乳组织，也是近年来研究表观遗传的经典案例。基因组印迹主要引起父母本源等位基因的差异表达。在植物中，基因组印迹集中发生在被子植物的胚乳组织,对胚乳和种子发育控制可能具有至关重要的作用。解析基因组印迹发生的分子机制是近年来表观遗传学和种子生物学研究的前沿领域。在最近的研究中,我们利用双子叶典型的胚乳型蓖麻种子鉴别了209个印迹基因，并发现这些基因可能参与胚乳储存物质的生物合成过程，但不知道这些印迹基因发生的分子调控机制。本研究拟通过DNA甲基化基因组测序和H3K27me3的免疫沉淀测序（CHIP-seq），利用已经鉴别的高密度父母本SNPs、鉴别分析表达差异的等位基因在基因组甲基化和组蛋白富集区域的特征，集中解析印迹基因发生的分子调控机理，有望为理解植物胚乳基因印迹发生的遗传机理、以及分析印迹基因的演化提供崭新的证据。

中文关键词： 表观遗传；基因印迹；DNA甲基化；蓖麻胚乳；组蛋白修饰

英文摘要： Genomic imprinting, a Non-Mendelian inheritance phenomenon, often results in parent-of-origin specific differential expression of maternally and paternally inherited alleles and arises mainly in placenta tissues of animals and endosperm tissues of seed plants. Genomic imprinting is also a typical case in epigenetic study. In plants, genomic imprinting arising mainly in the triploid endosperms of angiosperm may play critical roles in regulating the development of endosperm and formation of seed size. Currently, studies on genomic imprinting have come to be a cut-edge field in epigenetics and endosperm development. Very recently, we identified 209 imprinted genes from the hybrid seeds of castor bean (a model plant for seed biology researches), where endosperm persists through the seed development. However, the molecular mechanism underlying why these imprinted genes arose remains unknown. In this proposal, our study is focused on dissecting the potential regulation mechanism of imprinted genes arisen in castor bean endosperms using genomic DNA methylation sequencing and modified chromatin identification (based on genomic CHIP-seq). According to the genomic SNPs obtained from our previous study, the structural characteristics of DNA methylation and histone H3 lysine 27 trimethylation (H3K27me3) associated with differential expression of imprinted genes will be obtained by mapping against castor bean reference genome. Hopefully, this study would provide novel insights into understanding the molecular mechanisms regulating the differential expression of imprinted genes in plant endosperms.

英文关键词： epigenetics;gene imprinting;DNA methylation;endosperm of castor bean;histone modification