Regulation and Function of Active DNA Demethylation in Arabidopsis

拟南芥 DNA 主动去甲基化的调控和功能

基本信息

批准号：
8867250
负责人：
ROBERT L FISCHER
金额：
$ 32.96万
依托单位：
UNIVERSITY OF CALIFORNIA BERKELEY
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-02-01 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8867250
关键词：
Aberrant DNA Methylation Alleles Angiosperms Animal Model Arabidopsis Base Pairing Binding Proteins Cell physiology Cells Central Nervous System Neoplasms Chromatin Chromatin Structure Clinic Clinical Co-Immunoprecipitations Companions Complement Complex Congenital Disorders DNA DNA Methylation DNA Modification Methylases DNA Transposable Elements DNA biosynthesis DNA glycosylase Defect Derivation procedure Development Diagnostic Disease Disease Progression Embryo Epigenetic Process Failure Female Gene Expression Gene Mutation Gene Proteins Genes Genetic Genome Genomic Imprinting Genomic Segment Germ Cells Goals Hereditary Disease Histone H2A Histones Human In Vitro Inherited Lead Letters Malignant Neoplasms Mammals Mediating Medical Technology Methylation Modeling Molecular Chaperones Mouse-ear Cress Mutation Natural regeneration Neuraxis Nucleosomes Organ Parents Pathway interactions Patients Plants Play Procedures Production RNA Reagent Recruitment Activity Regulation Reproduction Research Role Sampling Site Small RNA Stem cells Stress Syndrome Technology Testing Therapeutic Intervention Tissues Variant abortion deep sequencing demethylation dimer egg embryo tissue human disease implantation imprint induced pluripotent stem cell male pluripotency prevent public health relevance research study sperm cell tumor progression zygote

项目摘要

DESCRIPTION (provided by applicant): DNA methylation is a crucial regulator of mammalian development. Mutations in DNA methyltransferases and methylcytosine binding protein genes cause genetic disease, and disrupted DNA methylation is a hallmark of cancer. Defects in DNA demethylation are associated with disorders of the central nervous system, tumor development, and failure to establish embryonic pluripotency. In addition, defective DNA demethylation prevents the in vitro derivation of induced pluripotent stem cells, a technology with the potential to be used in the clinic for the regeneration of cells, tissues and organs. Whereas most common model organisms lack DNA methylation, flowering plants, including Arabidopsis thaliana, share highly conserved methylation and demethylation pathways with mammals. Both plants and mammals use DNA methylation to regulate genomic imprinting - epigenetic marking and resultant gene expression only from an allele inherited from either the male or the female parent. We discovered that DNA demethylation catalyzed by the Arabidopsis DME DNA glycosylase occurs exclusively in companion cells, the central cell and the vegetative cell, which are adjacent to the gametes, the egg and sperm, respectively. One sperm fertilizes the central cell to generate the endosperm, a nutritive extra-embryonic tissue. A second sperm fertilizes the egg to form the embryo. We showed that gene imprinting occurs in the endosperm, which is established by DNA demethylation in the central cell. Moreover, our recent results suggest that DNA demethylation of central cell and vegetative cell genomes generates small RNAs that move to the adjacent gametes and silence transposable elements by the RNA-directed DNA methylation pathway. In Aim 1, we will test our model that DME-mediated DNA demethylation in companion cells functions to reinforce TE silencing in gametes. In Aim 2, we will elucidate the critical relationship between chromatin structure and targeted DNA demethylation. In Aim 3, we will identify new genes required for DNA demethylation. Our studies will lead to a detailed understanding of the epigenetic reprogramming catalyzed by DNA demethylation during plant sexual reproduction.

描述（由申请人提供）：DNA甲基化是哺乳动物发育的关键调节因子。 DNA 甲基转移酶和甲基胞嘧啶结合蛋白基因的突变会导致遗传性疾病，而 DNA 甲基化破坏是癌症的一个标志。 DNA 去甲基化缺陷与中枢神经系统疾病、肿瘤发育和胚胎多能性建立失败有关。此外，有缺陷的 DNA 去甲基化阻碍了诱导多能干细胞的体外衍生，而这是一项具有潜力的技术在临床上用于细胞、组织和器官的再生。虽然大多数常见的模式生物缺乏 DNA 甲基化，但包括拟南芥在内的开花植物与哺乳动物共享高度保守的甲基化和去甲基化途径。植物和哺乳动物都使用 DNA 甲基化来调节基因组印记 - 仅从雄性或雌性亲本遗传的等位基因进行表观遗传标记和由此产生的基因表达。我们发现拟南芥DME DNA糖基化酶催化的DNA去甲基化仅发生在分别与配子、卵子和精子相邻的伴细胞、中央细胞和营养细胞中。一个精子使中央细胞受精，产生胚乳，一种有营养的胚外组织。第二个精子使卵子受精形成胚胎。我们发现基因印记发生在胚乳中，这是通过中央细胞中的 DNA 去甲基化建立的。此外，我们最近的结果表明，中央细胞和营养细胞基因组的 DNA 去甲基化会产生小 RNA，这些小 RNA 会移动到相邻的配子，并通过 RNA 指导的 DNA 甲基化途径沉默转座元件。在目标 1 中，我们将测试我们的模型，即伴细胞中 DME 介导的 DNA 去甲基化可增强配子中的 TE 沉默。在目标 2 中，我们将阐明染色质结构与靶向 DNA 去甲基化之间的关键关系。在目标 3 中，我们将鉴定 DNA 去甲基化所需的新基因。我们的研究将有助于详细了解植物有性生殖过程中 DNA 去甲基化催化的表观遗传重编程。