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: 9238253
• 负责人: Humaira Gowher
• 金额: $ 32.09万
• 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/9238253
• 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; Recruitment Activity; Regulation; Regulator Genes; Regulatory Element; Repression; Role; Signal Pathway; Site; Specificity; 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; 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.

项目概要 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，如果失败 导致基因异常激活，进而调节导致癌症和脱发的信号通路 发育障碍。尽管有大量证据支持异常 DNA 甲基化在 几种人类疾病的病因学，调节靶点特异性的基本机制 de novo DNA MTase、Dnmt3a 和 3b 在很大程度上是未知的。基因抑制是一个精心策划的事件 涉及调控元件中辅激活复合物的丢失以及染色质状态的变化，包括 DNA甲基化的增加，导致稳定的基因抑制。最近的研究列举了 en-的作用 各种癌症中癌基因的癌基因介导的调节。其他人则表现出异常的plu-表达 全能基因介导多种癌症的去分化。增强染色质状态的变化 多能性基因的ers已被证明对于mu-期间多能性基因的抑制至关重要 胚胎干细胞（ESC）分化。 DNA甲基化在此过程中的作用及机制 在分化过程中将 DNA 甲基化靶向增强子的问题尚未得到解决。理解 增强子介导的多能性 (Pp) 建立所涉及的基本表观遗传机制 从长远来看，正常细胞分化期间的基因抑制将导致治疗药物的开发 恢复癌细胞中 Pp 基因抑制的策略。我们在此应用中的目标是阐明分子 使用在全基因组范围内调节 Pp 基因增强子处的 Dnmt3a 和 3b 活性的 lar 机制 ESC 分化作为模型系统。有我们强有力的初步数据和最近发表的研究的支持- 由于 Pp 基因增强子染色质状态的动态变化，我们将检验我们的假设，即 Lsd1- Mi2/NURD 活性充当 Pp 基因增强子的表观遗传开关，激活 Dnmt3 酶，导致 位点特异性 DNA 甲基化和稳定的 Pp 基因抑制。我们将进一步阐明染色质的作用 促进 Dnmt3a 和/或 3b 的增强子靶向活性至特定启动子的构象 ESC分化的ly期。为了测试 Dnmt3a 和 3b 是否都受到这些机制的调节，我们将绘制 它们在 ESC 分化过程中的全基因组活性。我们进行这些研究的理由是它们的成功 预计完成工作将填补我们对表观遗传“串扰”机制的理解空白。 细胞分化，调节 Dnmt3a/3b 活性以终止多能性程序，破坏其 可能导致发育障碍和癌症。此外，预计这些研究的结果 为了解各种表观遗传因素之间的相互作用如何影响基因表达提供新的见解， 归因于表型变异和跨代遗传。