De Novo Methyltransferase Function in Chromatin and Cancer

从头甲基转移酶在染色质和癌症中的功能

基本信息

批准号：
8735086
负责人：
Keith D Robertson
金额：
$ 25.72万
依托单位：
MAYO CLINIC ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-09-01 至 2018-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8735086
关键词：
Address Affect Alternative Splicing BTB/POZ Domain Binding Binding Sites Biological Models Cancerous Cell Culture Techniques Cell model Cells Characteristics Chromatin Chromatin Structure Complex DNA DNA Binding DNA Methylation DNA Methyltransferase DNA Modification Methylases DNA Polymerase II DNA Sequence Data Defect Development Disease Drug Targeting Embryo Embryonic Development Enzymes Epigenetic Process Event Exclusion Exons Family member Gene Expression Genes Genetic Transcription Genome Genome Mappings Genome Stability Genomic DNA Goals Growth Health Homeostasis Human Human Genome Hypermethylation Immunoprecipitation In Vitro Laboratories Light Link Malignant Epithelial Cell Malignant Neoplasms Mammalian Cell Maps Mass Spectrum Analysis Mediating Methylation Methyltransferase Modeling Modification Mutate Normal Cell Oncogenic Patients Pattern Process Promoter Regions Proteins Publishing RNA RNA Splicing Recruitment Activity Regulation Repetitive Sequence Research Role Somatic Cell Syndrome System Testing Thinking Time Work Zinc Fingers base cancer cell cell growth data mining exon skipping genome-wide in vivo methyl group neoplastic cell novel promoter public health relevance tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): DNA methylation is an essential regulator of transcription, chromatin structure, and development in mammalian cells mediated by the action of DNA methyltransferases DNMT1, DNMT3A, and DNMT3B. While critical for normal homeostasis, deregulated methylation patterns, characterized by repetitive element and gene body hypomethylation and promoter region hypermethylation, are a hallmark of tumor cells and an early event in tumorigenesis. Recent exciting findings, including whole genome mapping of DNMT binding sites from our laboratory and the marked enrichment of methylation in exons, pinpoint important functions for DNA methylation and DNMTs in intragenic regions. Identification of the new ICF syndrome gene ZBTB24 points to a novel class of DNMT targeting proteins. Collectively these and other findings make this an ideal moment to renew our long-time focus on de novo methyltransferase DNMT3B and take our research examining how it is targeted throughout the genome into a new and potentially paradigm-shifting direction. The central hypothesis to be tested in this application is that de novo methyltransferase DNMT3B is a major regulator of genomic DNA methylation patterns in normal cells and that disruption of its functions through aberrant targeting contributes to DNA methylation defects in cancer. Specifically in this application, we propose that DNMT3B targeting is regulated by aspects of chromatin and sequence-specific features/factors (including ZBTB24), and that a major function of these interactions in normal cells is to recruit DNA methylation to intragenic loci to regulate alternative RNA splicing. We will test this hypothesis with three specific aims. In aim 1 we will define chromatin and DNA sequence determinants characteristic of loci bound by DNMT3B and targeted for DNA methylation in a model differentiation system. In aim 2 we will investigate how DNMT3B is recruited to intragenic regions and how its DNA methylation activity influences alternative splicing (specifically exon skipping). Finally, in aim 3 we will characterize the newly discovered ICF Syndrome gene ZBTB24 (ZNF450) and determine how it regulates DNMT3B and DNA methylation targeting. Addressing this hypothesis has the potential to radically change how we think of the functions of methylation (regulating splicing) and how methylation is targeted throughout the genome (via ZBTB family members) under normal and pathological conditions. Intragenic loci are an evolutionarily conserved seat for DNA methylation. Our studies will shed new light on how the frequent, but poorly studied, hypomethylation that occurs in cancer cells may drive aberrant cell growth through altered RNA splicing rather than through transcriptional silencing. This is expected to positively affect human health by allowing for a more complete understanding of the functions of methylation in different regions of the genome, which should enhance our ability to develop novel therapies to correct aberrant methylation or use it as a drug target.

描述（由申请人提供）：DNA甲基化是通过DNA甲基转移酶DNMT1，DNMT3A和DNMT3B介导的转录，染色质结构和发育的必不可少的调节剂。尽管对于正常的稳态至关重要，但以重复性元素和基因体低甲基化和启动子区域高甲基化为特征的甲基化模式是肿瘤细胞的标志，是肿瘤发生的早期事件。最近的令人兴奋的发现，包括我们实验室的DNMT结合位点的整个基因组图和外显子中甲基化的明显富集，确定了内基因区域DNA甲基化和DNMT的重要功能。新的ICF综合征基因ZBTB24的鉴定指向一类新的DNMT靶向蛋白质。这些发现和其他发现使这是一个理想的时刻，可以更新我们对从头甲基转移酶DNMT3B的长期关注，并将我们的研究探讨如何将其靶向整个基因组的靶向到一个新的且潜在的范式转移方向。在此应用中要测试的中心假设是，从头开始的甲基转移酶DNMT3B是正常细胞中基因组DNA甲基化模式的主要调节剂，并且通过异常靶向促进其功能会导致癌症中的DNA甲基化缺陷。在此应用中，我们提出，DNMT3B靶向受染色质和序列特异性特异性/因素的各个方面（包括ZBTB24）调节，并且这些相互作用在正常细胞中的主要功能是募集DNA甲基化至基因内基因座，以调节替代RNA的替代RNA plinagicative替代RNA。我们将以三个特定的目标检验这一假设。在AIM 1中，我们将定义由DNMT3B结合的基因座的染色质和DNA序列决定因素的特征，并靶向模型分化系统中的DNA甲基化。在AIM 2中，我们将研究如何将DNMT3B募集到基因内区域，以及其DNA甲基化活性如何影响替代剪接（特别是外显子跳过）。最后，在AIM 3中，我们将描述新的发现了ICF综合征基因ZBTB24（ZNF450），并确定如何调节DNMT3B和DNA甲基化靶向。解决这一假设有可能从根本上改变我们对甲基化功能（调节剪接）的想法以及在正常和病理条件下如何针对整个基因组（通过ZBTB家族成员）的甲基化的方式。基因基因座是用于DNA甲基化的进化保守的座椅。我们的研究将为癌细胞中发生的频繁但研究不足的降低甲基化的频率降低可能会通过改变的RNA剪接而不是通过转录沉默来驱动异常的细胞生长。预计这将通过对基因组不同区域中甲基化功能的更全面了解，从而积极影响人类健康，这应该增强我们开发新疗法以纠正异常甲基化或将其用作药物靶标的能力。