Regulation and Function of DNA Demethylation in Arabidopsis

拟南芥DNA去甲基化的调控和功能

基本信息

批准号：
8061988
负责人：
ROBERT L FISCHER
金额：
$ 30.09万
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 2013-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8061988
关键词：
Acetylation Address Affect Alleles Amino Acids Animals Arabidopsis Arabidopsis DEMETER protein Binding Binding Proteins Biochemical Biological Assay Cell Nucleus Cells Chimeric Proteins Chromatin Chromatin Structure Cis-Acting Sequence Cytosine DNA DNA Methylation DNA Repair DNA Repair Pathway DNA glycosylase Data Disease Disease Resistance Embryonic Development Enzymes Epigenetic Process Excision Family Family member Gene Expression Gene Expression Regulation Gene Proteins Gene Silencing Gene Targeting Genes Genetic Transcription Genome Genomics Heterochromatin Histones Hypermethylation In Vitro Infection Insertion Mutation Length Link Mammals Maps Measures Mediating Methylation Molecular Mutation Nucleosomes Placenta Plant Diseases Plants Play Polycomb Predisposition Process Protein Binding Proteins Pseudomonas syringae RNA Polymerase II Regulation Reproduction Research Resistance Retroviridae Role Stem cells Structure Substrate Specificity System T-DNA Testing Trans-Activators Transcription factor genes Vertebral column X ray diffraction analysis X-Ray Crystallography X-Ray Diffraction bacterial resistance base defense response demethylation density enzyme activity gene function genome-wide histone modification homeodomain imprint insight member mutant novel pathogen polypeptide promoter research study sperm cell tumor progression

项目摘要

DESCRIPTION (provided by applicant): DNA methylation (5-methylcytosine) in mammals and plants silences transposons, retroviruses, and regulates gene imprinting. In mammals, DNA hypermethylation is associated with certain diseases including the onset and progression of cancer. We discovered that the Arabidopsis DEMETER (DME) protein regulates imprinting by DNA demethylation. DME is related to DNA glycosylases that excise damaged/mispaired bases in the base excision DNA repair pathway. DME excises 5-methylcytosine that is replaced with cytosine. DME is expressed primarily in the central cell, the progenitor of the placenta-like endosperm that supports embryo development. DME demethylates and activates maternal allele expression of genes that are imprinted in the endosperm. Arabidopsis has three DME-LIKE (DML) genes: ROS1, DML2, and DML3, which are broadly expressed in the plant. Like DME, they excise 5-methylcytosine and have a DNA glycosylase domain flanked by additional conserved domains that are essential for activity. DME and DML proteins specifically demethylate the 5' and 3' ends of at least 180 genes. ROS1 demethylates disease resistance genes and is required for resistance to a bacterial pathogen, Pseudomonas syringae. We will carry out the following experiments to understand the mechanisms and functions of DNA demethylation in the regulation of gene imprinting. 1) We will elucidate how expression of DME is restricted to the central cell, identify new genes imprinted by DME, and isolate mutations in genes that regulate DME expression, targeting, and/or DNA demethylation. 2) To understand the molecular mechanisms of DNA demethylation, we will identify and analyze the function of DME-binding proteins, determine if DME directly demethylates DNA by physical association with its target genes, and elucidate what changes in chromatin structure accompany DNA demethylation. 3) To understand how DNA demethylation regulates disease resistance, we will elucidate the function of plant defense genes that are demethylated by ROS1. Plants and animals have related mechanisms for controlling DNA methylation. Information about the basic mechanisms of DNA demethylation will provide valuable insights into the critical role DNA methylation plays in the regulation of gene imprinting and disease

描述（由申请人提供）：哺乳动物和植物中的 DNA 甲基化（5-甲基胞嘧啶）可沉默转座子、逆转录病毒并调节基因印记。在哺乳动物中，DNA 高甲基化与某些疾病相关，包括癌症的发生和进展。我们发现拟南芥 DEMETER (DME) 蛋白通过 DNA 去甲基化调节印记。 DME 与 DNA 糖基化酶相关，DNA 糖基化酶在碱基切除 DNA 修复途径中切除受损/错配的碱基。 DME 切除 5-甲基胞嘧啶，并用胞嘧啶取代。 DME 主要在中央细胞中表达，中央细胞是支持胚胎发育的胎盘样胚乳的祖细胞。 DME 去甲基化并激活胚乳中印记基因的母体等位基因表达。拟南芥具有三个 DME-LIKE (DML) 基因：ROS1、DML2 和 DML3，在植物中广泛表达。与 DME 一样，它们切除 5-甲基胞嘧啶，并具有 DNA 糖基化酶结构域，两侧是对于活性至关重要的额外保守结构域。 DME 和 DML 蛋白特异性地使至少 180 个基因的 5' 和 3' 末端去甲基化。 ROS1 使抗病基因去甲基化，并且是抵抗细菌病原体丁香假单胞菌所必需的。我们将进行以下实验来了解DNA去甲基化在基因印记调控中的机制和功能。 1）我们将阐明DME的表达如何限制在中央细胞，识别DME印记的新基因，并分离调节DME表达、靶向和/或DNA去甲基化的基因突变。 2）为了了解DNA去甲基化的分子机制，我们将鉴定和分析DME结合蛋白的功能，确定DME是否通过与其靶基因的物理关联直接使DNA去甲基化，并阐明DNA去甲基化伴随着染色质结构的变化。 3）为了了解DNA去甲基化如何调节抗病性，我们将阐明被ROS1去甲基化的植物防御基因的功能。植物和动物具有控制DNA甲基化的相关机制。有关 DNA 去甲基化基本机制的信息将为了解 DNA 甲基化在基因印记和疾病调节中的关键作用提供有价值的见解