Non-canonical functions of chromatin insulators and Polycomb-group proteins

基因转录的变化在癌症的进展中很重要，在大多数其他人类疾病中，以及 在衰老过程中，以及在多细胞生物体发育的各个阶段。一个完整的 了解这些变化是如何被调控的，是诊断工具和干预策略的基础。 进一步的进步带来了新方法的前景，并提高了当前 接近了。在果蝇中可用的工具使研究基因调控机制成为可能 细节，在真实的活体环境中。本研究旨在研究染色质基因调控的机制。 涉及多梳响应元件(PRE)和绝缘体(包括名为HOMIE的绝缘体)，这些元件可在 被充分描述的果蝇基因甚至跳过了。这些研究将解决以下基本问题： 调节转录记忆和染色体组织的调节DNA在 核内有3个维度。它们将提供对表观遗传机制的更清晰的理解 传播可选择的转录状态，以及染色体结构域组织如何影响基因 表情。这些研究的一个独特贡献是将这些机制与那些调解 发育背景下的增强子-启动子相互作用。在哺乳动物中，多梳状蛋白和 绝缘体参与维持干细胞的特性、发育决策和剂量。 补偿，以及在肿瘤发生和遗传性人类疾病中。具体目标是： 目的1.确定保守的DNA结合多梳基(PcG)蛋白的同源同源异型(Pho) 维持果蝇的活跃和抑制状态，甚至跳过(EVE)基因表达。 确定调控EVE的新表观遗传机制如何在全基因组范围内部署。 这些研究的结果将把表观基因调控领域推向新的领域，揭示 对发育和成人组织维护都有全新的影响。 目标2.确定通读转录如何抑制增强子功能以及这种抑制是如何进行的 受多梳结构域的影响，在前夕和整个基因组。 这里的研究将探索一种新的方式，在这种方式下，转录行为调节基因，导致 适用于全基因组的机械洞察力。 目标3.确定一些启动子启动高度进行性转录的机制 通过障碍，如聚(A)加法信号，而其他人不这样做。 过程转录对基因表达和染色体结构的影响超过了 染色体上的距离。它的监管和影响才刚刚开始被理解。我们有 开发了一种灵敏的分析系统，将使我们在机械化方面取得快速进展 理解。

Changes in gene transcription are important in the progression of cancer, in most other human diseases, and in the aging process, as well as in the development of multicellular organisms at all stages. A full understanding of how such changes are regulated is the basis of diagnostic tools and intervention strategies. Further advancement holds the promise of novel approaches, and of increased effectiveness of current approaches. Tools available in Drosophila make it possible to study gene regulatory mechanisms in great detail, in a true in vivo context. This proposal is to study mechanisms of chromatin-based gene regulation involving Polycomb-response elements (PREs) and insulators (including one named homie) that are found in the well-characterized Drosophila gene even skipped. These studies will address basic questions of how regulatory DNA that mediates transcriptional memory and chromosome organization carries out its function in 3 dimensions in the nucleus. They will provide a clearer understanding of how epigenetic mechanisms propagate alternative transcriptional states, and how chromosomal domain organization affects gene expression. A unique contribution of these studies is to integrate these mechanisms with those mediating enhancer-promoter interactions in a developmental context. In mammals, Polycomb-group proteins and insulators are involved in the maintenance of stem cell identity, developmental decisions, and dosage compensation, as well as in oncogenesis and inherited human disorders. The Specific Aims are: Aim 1. Determine how the conserved, DNA binding Polycomb-group (PcG) protein Pleiohomeotic (Pho) maintains both the active and the repressed state of Drosophila even skipped (eve) gene expression. Determine how novel epigenetic mechanisms that regulate eve are deployed genome-wide. Results from these studies will propel the field of epigenetic gene regulation into novel territory, uncovering entirely new influences on both development and adult tissue maintenance. Aim 2. Determine how read-through transcription represses enhancer function and how this repression is influenced by Polycomb domains, at eve and throughout the genome. Studies here will explore a new way in which the very act of transcription regulates genes, leading to mechanistic insights that apply genome-wide. Aim 3. Determine mechanisms whereby some promoters initiate highly processive transcription that reads through barriers, such as poly(A) addition signals, while others do not. Processive transcription has the power to influence gene expression and chromosome architecture over great distances along a chromosome. Its regulation and influence are just beginning to be understood. We have developed a sensitive assay system that will allow us to make rapid progress toward a mechanistic understanding.