Transcriptional Regulation by Epigenetic Factors

表观遗传因素的转录调控

• 批准号: 9915931
• 负责人: ALEXANDER M MAZO
• 金额: $ 31.98万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9915931
• 关键词: Address; Biological; Biological Assay; Cell Cycle; Cell Differentiation process; Cell division; Cells; Cellular Assay; Chromatin; Chromatin Structure; Complex; Conflict (Psychology); DNA; DNA Polymerase II; DNA biosynthesis; DNA-Directed RNA Polymerase; Data; Daughter; Development; Disease; Elongation Factor; Ensure; Epigenetic Process; Foundations; Future; Gene Expression; Gene Expression Regulation; Generations; Genes; Genetic Transcription; Health; Heart; Histones; Kinetics; Malignant Neoplasms; Memory; Microscopy; Modeling; Molecular Conformation; Monitor; Nature; Normal Cell; Nuclear; Nucleosomes; Pattern; Play; Process; Proliferating; Proteins; Publishing; RNA; RNA Stability; RNA chemical synthesis; Regulatory Element; Repression; Research; Resolution; Role; Solid; TATA-Box Binding Protein; Testing; Time; Transcriptional Elongation Factors; Transcriptional Regulation; Travel; base; cell regeneration; daughter cell; design; drug discovery; epigenetic regulation; experimental study; novel strategies; programs; protein complex; recruit; restoration; stem cell differentiation; stem cells; theories; transcription factor

Project Summary: Cell memory plays a key role during differentiation and disease. It relies on epigenetic inheritance that is essential to propagate gene expression program through cell generation, in large part through maintaining the structure of chromatin in daughter cell. DNA replication is the major obstacle in conservation of chromatin structure. During replication, most proteins are thought to dissociate from DNA. A few molecules may remain associated with DNA, thus marking DNA regulatory elements for future maturation of chromatin into an open or compact conformation. The identity of these epigenetic marks is unknown. The best candidates are thought to be modified histones because they are assumed to transfer from the parental to daughter nucleosomes on nascent DNA. However, until recently, there were no experimental approaches to directly examine neither the nature of epigenetic marks, nor the order and timing of recruitment of chromosomal proteins to DNA following replication. Similarly, we know very little about how and when transcription resumes after DNA replication. We developed several new experimental approaches that allow addressing these key epigenetic issues, and found that the structure of chromatin is not as severely disrupted as is currently suggested. RNA Polymerase II and related general transcription and elongation factors are found on nascent DNA just after replication. Moreover, even immature RNAs are found in the proximity to nascent DNA suggesting that the RNA Pol II – RNA complex is able to survive DNA replication. We also found that transcription resumes relatively quickly after DNA replication. Based on our published and preliminary results, we propose to test a new epigenetic concept suggesting that once transcription is established, most of the transcriptional apparatus may be associated with DNA through replication, thus serving as an epigenetic mark for active genes. This possibility, however, conflicts with the conventional model suggesting that transcription and replication complexes travel along DNA, since this will lead to collisions of these protein complexes. To resolve this contradiction, we will test the hypothesis that the stability of the transcriptional machinery through replication can be resolved if transcription and replication occur in the stationary nuclear sub-domains, transcription and replication factories, and that DNA is reeled through these protein factories. The results of these experiments will greatly contribute to our understanding of the epigenetic processes, and may have a major impact on developing new approaches in many biological and drug discovery fields.

项目摘要： 细胞记忆在分化和疾病中起关键作用。它依赖于表观遗传 这对于通过细胞生成传播基因表达程序至关重要，在很大程度上是通过 保持子细胞中染色质的结构。 DNA复制是主要障碍 染色质结构的保护。在复制过程中，大多数蛋白质被认为与 脱氧核糖核酸。一些分子可能与DNA有关，从而标记了DNA调节元件 将染色质的未来成熟到开放或紧凑的构象中。这些表观遗传学的身份 标记是未知的。认为最好的候选人被认为是修饰的组蛋白 在新生DNA上从父母转移到子核小体。但是，直到最近， 没有实验方法直接检查表观遗传标记的性质，也没有 复制后，染色体蛋白募集到DNA的顺序和时间。同样，我们知道 关于DNA复制后的转录方式以及何时恢复的内容很少。 我们开发了几种允许解决这些关键表观遗传的新实验方法 问题，发现染色质的结构并不像目前建议的那样严重破坏。 RNA聚合酶II和相关的一般转录和伸长因子在新生的DNA上发现 复制后。此外，在与新生DNA的接近性中也发现了未成熟的RNA 提示RNA POL II - RNA复合物能够在DNA复制中存活。我们还发现 DNA复制后，转录恢复相对较快。基于我们出版的初步 结果，我们建议测试一种新的表观遗传概念，表明一旦建立了转录， 大多数转录设备可能通过复制与DNA有关，从而作为一个 活性基因的表观遗传标记。但是，这种可能性与传统模型冲突 提示转录和复制复合物沿DNA传播，因为这将导致碰撞 这些蛋白质复合物。为了解决这一矛盾，我们将检验以下假设。 如果转录和复制发生在 固定的核子域，转录和复制工厂，并将DNA卷入 通过这些蛋白质因子。这些实验的结果将极大地促进我们的 了解表观遗传过程，可能会对开发新的影响产生重大影响 许多生物学和药物发现领域的方法。