Regulation of DNA methylation homeostasis in Arabidopsis

拟南芥 DNA 甲基化稳态的调控

基本信息

批准号：
9534692
负责人：
Mary Gehring
金额：
$ 38.17万
依托单位：
WHITEHEAD INSTITUTE FOR BIOMEDICAL RES
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-08-07 至 2020-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9534692
关键词：
Aberrant DNA Methylation Address Arabidopsis Base Excision Repairs Biological Biological Models Code Conflict (Psychology)Critical Pathways Cytosine DNA DNA Methylation DNA Methylation Regulation DNA Modification Methylases DNA Transposable Elements DNA glycosylase Data Development Disease ENG gene Ensure Epigenetic Process Equilibrium Eukaryota Fertilization Gene Expression Gene Silencing Genes Genetic Genetic Screening Genetic Transcription Genome Genome Stability Genomic Imprinting Genomic approach Genomics Germ Cells Goals Growth and Development function Homeostasis Hypermethylation Joints Light Maintenance Malignant Neoplasms Mammals Mediating Methylation Molecular Mutagenesis Mutate Mutation Pathway interactions Pattern Phenotype Plant DNA Plant Genome Plants Process RNA ROS1 gene Recovery Regulation Repression Research Source System Testing Tissues Transcript Transcriptional Regulation Transcriptional Silencer Elements Untranslated RNA X Inactivation base demethylation epigenome epigenomics genome-wide luminescence male methylation pattern methylation testing methylome mutant novel offspring plant growth/development public health relevance reproductive development response sperm cell

项目摘要

DESCRIPTION (provided by applicant): DNA methylation is critical for essential processes including genomic imprinting, X-inactivation, transposable element silencing, and genome stability. DNA methylation patterns are the result of active DNA methylation and demethylation processes. Arabidopsis represents an excellent eukaryotic model system to dissect the functions and mechanisms of methylation and demethylation because of its facile genetics and genomics and the conservation of these processes with mammals. Arabidopsis has been a continued source of novel discoveries in the field of epigenetics. The function and regulation of DNA demethylation is under studied compared to processes that promote DNA methylation, partly because the mechanisms of active DNA demethylation have been elucidated only relatively recently. In plants, DNA demethylation is mediated by 5- methylcytosine (5-mC) DNA glycosylases that remove 5-mC from DNA by base excision repair, leading to its replacement with unmodified cytosine. Expression of the 5-mC DNA glycosylase ROS1 is significantly reduced in response to mutations in components of the maintenance methylation and RNA-directed DNA methylation (RdDM) pathways. This suggests that there is a molecular crosstalk between the methylation and demethylation pathways to achieve a cellular balance of these antagonistic enzymatic activities. The long-term goal of this research is to define the molecular mechanisms that ensure DNA methylation homeostasis during plant growth and development and to determine the functional consequences of perturbing that homeostasis. The proposed research focuses on ROS1, a locus where multiple epigenetic pathways converge to modulate DNA demethylase expression in response to global and local changes in DNA methylation. We will determine why and how ROS1 transcription is reduced in response to the disruption of the RdDM pathway. We will identify regulators of this process through a novel genetic screen that will identify genes that promote expression of ROS1 in a methylation deficient background. Finally, we will determine whether the decreased expression of ROS1 that occurs during wild type sperm development in response to reduced DNA methylation is responsible for establishing proper genome-wide DNA methylation patterns after fertilization. These efforts will significantly increase our understanding of how the activity of epigenetic pathways is modulated in response to the state of the epigenome. Our findings will be directly applicable to mammals and other eukaryotes that control their genome through DNA methylation based mechanisms.

描述（由应用提供）：DNA甲基化对于包括基因组印迹，X灭活，可转座元件沉默和基因组稳定性在内的基本过程至关重要。 DNA甲基化模式是活性DNA甲基化和脱甲基化过程的结果。拟南芥代表了一种出色的真核模型系统，用于剖析甲基化和脱甲基化的功能和机制，因为其易于遗传学和基因组学以及用哺乳动物对这些过程的保存。拟南芥一直是表观遗传学领域中新发现的持续来源。与促进DNA甲基化的过程相比，DNA脱甲基化的功能和调节在研究下，部分原因是仅仅阐明了活性DNA脱甲基化的机制。在植物中，DNA脱甲基化是由5-甲基霉素（5-MC）DNA糖基酶介导的，该甲基糖基酶通过基本惊喜修复从DNA中去除5-MC，从而用未修饰的胞嘧啶替换。 5-MC DNA糖基酶ROS1的表达显着降低，响应于维持甲基化和RNA指导的DNA甲基化（RDDM）途径的突变。这表明甲基化和去甲基化途径之间存在分子串扰，以实现这些拮抗酶活性的细胞平衡。这项研究的长期目标是定义确保在植物生长和发育过程中确保DNA甲基化稳态的分子机制，并确定扰动该稳态的功能后果。拟议的研究集中在ROS1上，ROS1是一种局部，其中多个表观遗传途径会收敛以调节DNA脱甲基酶表达，以响应DNA甲基化的全球和局部变化。我们将确定为什么ROS1转录因RDDM途径的破坏而减少。我们将通过新的遗传筛选来确定该过程的调节因子，该遗传筛选将鉴定出在甲基化确定背景下促进ROS1表达的基因。最后，我们将确定响应于DNA甲基化降低的野生型精子发育过程中ROS1的表达降低是否负责在受精后建立适当的全基因组DNA甲基化模式。这些努力将大大提高我们对表观遗传途径的活性如何根据表观遗传组的状态调节的理解。我们的发现将直接适用于通过基于DNA甲基化机制来控制其基因组的哺乳动物和其他真核生物。