Regulation of Dnmt3 Activity at Enhancers of Cell Identity Genes During Differentiation

分化过程中细胞识别基因增强子 Dnmt3 活性的调节

• 批准号: 9975859
• 负责人: Humaira Gowher
• 金额: $ 32.05万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9975859
• 关键词: Aberrant DNA Methylation; Active Sites; Address; Affect; Binding; Biological Models; Cell Differentiation process; Cell Line; Cell Nucleus; Cells; Chromatin; Chromatin Loop; Complex; DNA Methylation; DNA Methylation Regulation; DNA Modification Methylases; DNMT3B gene; DNMT3a; Data; Development; Disease; Ear; Embryonic Development; Enhancers; Enzymes; Epigenetic Process; Etiology; Event; Failure; Gene Activation; Gene Expression; Genes; Genomic Instability; Germ Lines; Goals; Histone Acetylation; Histones; Homeostasis; In Vitro; KDM1A gene; Lead; Location; Maintenance; Malignant Neoplasms; Maps; Measures; Mediating; Methods; Methylation; Methyltransferase; Molecular; Molecular Conformation; Mus; Names; Normal Cell; NuRD complex; Oncogene Activation; Oncogenes; Outcome Study; Pathway interactions; Pattern; Phase; Phenotype; Process; Publishing; Regulation; Regulator Genes; Regulatory Element; Repression; Role; Signal Pathway; Site; Specificity; Structure; Suppressor Genes; Tail; Testicular Carcinoma; Testing; Therapeutic Intervention; Treatment Efficacy; Variant; cancer cell; demethylation; developmental disease; embryonic stem cell; gene repression; genome integrity; genome-wide; histone methylation; human disease; in vitro activity; insight; novel; novel therapeutic intervention; novel therapeutics; pluripotency; prevent; programs; promoter; recruit; stem cell differentiation; therapeutic development; transgenerational epigenetic inheritance; tumorigenesis

Project Summary Maintenance of proper patterns of DNA methylation is essential for the integrity of cell identity, failure of which results in aberrant activation of genes, which in turn modulates signaling pathways leading to cancer and de- velopmental disorders. Despite a large body of evidence supporting the role of aberrant DNA methylation in etiology of several human diseases, the fundamental mechanisms that regulate the target site specificity of the de novo DNA MTases, Dnmt3a and 3b, are largely unknown. Gene repression is an orchestrated event that involves loss of coactivator complexes from the regulatory elements and changes in chromatin state including gain of DNA methylation, resulting in stable gene repression. Recent studies have enumerated the role of en- hancer-mediated regulation of oncogenes in various cancers. Others have shown aberrant expression of plu- ripotency genes mediates dedifferentiation in several cancers. Changes in the chromatin state of the enhanc- ers of pluripotency genes have been shown to be critical for the repression of pluripotency genes during mu- rine embryonic stem cell (ESC) differentiation. The role of DNA methylation in this process and the mechanism that targets DNA methylation to the enhancers during differentiation have not been addressed. Understanding the fundamental epigenetic mechanisms involved in the establishment of enhancer-mediated pluripotency (Pp) gene repression during normal cell differentiation will, in the long-term, lead to development of therapeutic strategies to restore Pp gene repression in cancer cells. Our objective in this application is to elucidate molecu- lar mechanism(s) that regulate the activity of Dnmt3a and 3b at enhancers of Pp genes genome-wide using ESC differentiation as a model system. Supported by our strong preliminary data and recently published stud- ies on the dynamics of the chromatin state of Pp gene enhancers, we will test our hypothesis that Lsd1- Mi2/NURD activity acts as an epigenetic switch at Pp gene enhancers to activate Dnmt3 enzymes, causing site-specific DNA methylation and stable Pp gene repression. We will further elucidate the role of chromatin conformation in facilitating enhancer-targeted activity of Dnmt3a and/or 3b to specific promoters during the ear- ly phase of ESC differentiation. To test if both Dnmt3a and 3b are regulated by these mechanisms, we will map their genome-wide activity during ESC differentiation. Our rationale for these studies is that their successful completion is expected to fill the gap in our understanding of how the epigenetic “cross talk” mechanisms, dur- ing cell differentiation, modulate Dnmt3a/3b activity to terminate the pluripotency program, disruption of which could lead to developmental disorders and cancer. Additionally, the outcomes from these studies are expected to provide new insights into how the interplay between various epigenetic factors affects gene expression, con- tributing to phenotypic variation and transgenerational inheritance.

项目摘要 维持正确的DNA甲基化模式对于细胞身份的完整性至关重要，其失败 导致基因的异常激活，这反过 速度疾病。尽管有大量证据支持异常DNA甲基化的作用 几种人类疾病的病因，这是调节目标位点特异性的基本机制 从头DNA MTases，DNMT3A和3B，在很大程度上是未知的。基因表达是一个精心策划的事件 涉及从调节元件中失去共激活因子复合物以及染色质状态的变化，包括 DNA甲基化的增益，导致稳定的基因表达。最近的研究列举了恩的作用 在各种癌症中对癌基因的调节。其他人显示出异常的表达 成熟基因介导了几种癌症的去分化。增强的染色质状态的变化 多能基因的ERS已被证明对于在Mu-中表达多能基因的表达至关重要 Rine胚胎干细胞（ESC）分化。 DNA甲基化在此过程和机制中的作用 在分化过程中靶向DNA甲基化的增强剂尚未得到解决。理解 建立增强子介导的多能性（PP）涉及的基本表观遗传机制 长期，正常细胞分化过程中的基因表达将导致治疗的发展 恢复癌细胞中PP基因表达的策略。我们在此应用中的目标是阐明分子 LAR机制使用PP基因的增强子在全基因组的增强子上调节DNMT3A和3B的活性 ESC分化为模型系统。在我们强大的初步数据的支持下，最近发表了研究 IE关于PP基因增强子的染色质状态的动力学，我们将测试LSD1-的假设 MI2/NURD活性充当PP基因增强子的表观遗传转换，以激活DNMT3酶，从而导致 位点特异性DNA甲基化和稳定的PP基因表达。我们将进一步阐明染色质的作用 在促进DNMT3A和/或3B的促进者对特定启动子的构构中， LY ESC分化阶段。为了测试DNMT3A和3B是否受这些机制调节，我们将绘制 他们在ESC分化过程中全基因组活性。我们对这些研究的理由是他们的成功 预计完成将填补我们对表观遗传学“谈话”机制如何，持续的理解的空白 ING细胞分化，调节DNMT3A/3B活性以终止多能计划 可能导致疾病和癌症。此外，预期这些研究的结果 为了提供有关各种表观遗传因素之间相互作用如何影响基因表达的新见解 向表型变异和变革性继承提供支持。