Functional analysis of the TET2/OGT complex in epigenetic modifications

表观遗传修饰中 TET2/OGT 复合物的功能分析

基本信息

批准号：
9221349
负责人：
Xiaochun Yu
金额：
$ 32.3万
依托单位：
BECKMAN RESEARCH INSTITUTE/CITY OF HOPE
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：
2015-01-01 至 2018-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9221349
关键词：
Acute Myelocytic Leukemia Affinity Chromatography Area Cell physiology Chromatin Chromosomes Chronic Myelomonocytic Leukemia Complex CpG dinucleotide Cytosine DNA DNA Methylation DNA Modification Methylases DNA Sequence Alteration Defect Dysmyelopoietic Syndromes Enzymes Epigenetic Process Family Genes Genetic Transcription Genomic DNA Genomic Instability HDAC1 gene Histone Acetylation Histones Hypermethylation In Vitro Induced Mutation Loss of Heterozygosity Lysine Malignant Neoplasms Methylation Missense Mutation Modification Molecular Mus Mutate Mutation Myelodysplastic/Myeloproliferative Disease Myelogenous Myeloproliferative disease O-GlcNAc transferase Oxides Patients Play Positioning Attribute Promoter Regions Proteins Pyrimidine Recurrence Reporting Research Role Somatic Mutation Syndrome Transcriptional Activation Tumor Suppression Tumor Suppressor Genes carcinogenesis chromatin remodeling demethylation embryonic stem cell epigenetic regulation gene repression genome-wide histone acetyltransferase in vivo leukemogenesis methyl group microdeletion novel oxidation peptide O-linked N-acetylglucosamine-beta-N-acetylglucosaminidase public health relevance tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): Epigenetic modifications play an important role in chromatin remodeling. One typical example of these epigenetic modifications is DNA methylation. Methylation of DNA is mainly occurred at the 5 position of the cytosine pyrimidine ring in a CpG dinucleotide context, which is catalyzed by DNA methyltransferases. DNA methylation changes the status of chromatin and regulates numerous molecular cellular processes. Recently, TET family enzymes were shown to oxidize the methylated cytosine in a step towards DNA demethylation. These enzymes specifically convert methylated cytosine (5mC) mainly into hydroxymethylated cytosine (5hmC). Interestingly, unlike DNA demethylation, TET enzymes-dependent oxidation of methylated cytosine is not only associated with transcription activation but also transcription repression. It has been reported that TET1 forms a complex with SIN3A and HDAC1/2, which is involved in transcription repression. To study the molecular mechanism of TET enzyme-dependent DNA demethylation, we examined the associated proteins of TET enzymes using an unbiased protein affinity purification approach, and found OGT as a functional partner of TET2 in mouse ES cells. OGT is the only enzyme that uses UDP-GlcNAc as the donor to catalyze protein O-GlcNAcylation. Our preliminary study shows that OGT interacts with TET2 to form a heterodimer and is targeted to chromatin for histone GlcNAcylation via TET2 in mouse ES cells. Genome- wide profiling of TET2 and OGT suggests that TET2, OGT and OGT-dependent histone GlcNAcylation are associated with active gene transcription in mouse ES cells. Moreover, TET2 is one of the most frequently mutated genes in myeloid malignancies, suggesting that genetic mutations induce abnormal epigenetic modifications during carcinogenesis. Thus, in this application, we plan to examine the molecular mechanism of the TET2/OGT complex in epigenetic regulation as well as its role in tumorigenesis. The proposed study will reveal a novel mechanism of how somatic mutations deregulate several types of epigenetic modification, which may result tumorigenesis.

描述（由申请人提供）：表观遗传修饰在染色质重塑中起重要作用。这些表观遗传修饰的一个典型例子是DNA甲基化。 DNA的甲基化主要发生在CpG二核苷酸环境中的胞嘧啶嘧啶环的5个位置，该环境由DNA甲基转移酶催化。 DNA甲基化会改变染色质的状态，并调节许多分子细胞过程。最近，显示TET家族酶在迈向DNA脱甲基的一步中氧化甲基化的胞嘧啶。这些酶特异性转化为主要转化为甲基化的胞嘧啶（5MC），主要转化为羟基化胞嘧啶（5HMC）。有趣的是，与DNA脱甲基化不同，甲基化胞嘧啶的TET酶依赖性氧化不仅与转录激活，而且与转录抑制有关。据报道，TET1与SIN3A和HDAC1/2形成复合物，该复合物与转录抑制有关。为了研究TET酶依赖性DNA脱甲基化的分子机制，我们使用无偏的蛋白质亲和力纯化方法检查了TET酶的相关蛋白，并发现OGT是小鼠ES细胞中TET2的功能伙伴。 OGT是唯一使用UDP-GLCNAC作为供体催化蛋白O-Glcnacylation的供体的酶。我们的初步研究表明，OGT与TET2相互作用以形成异二聚体，并针对小鼠ES细胞中TET2的组蛋白Glcnacylation靶向染色质。 TET2和OGT的基因组分析表明，TET2，OGT和OGT依赖性组蛋白Glcnacylation与小鼠ES细胞中的活性基因转录有关。此外，TET2是髓样恶性肿瘤中最常见的突变基因之一，表明遗传突变会在癌变期间诱导异常的表观遗传修饰。因此，在此应用中，我们计划检查表观遗传调节中TET2/OGT复合物的分子机制及其在肿瘤发生中的作用。拟议的研究将揭示一种新的机制，即体细胞突变如何消除几种类型的表观遗传修饰，这可能会导致肿瘤发生。