Hormonal and Developmental Regulation of Gene Expression

描述(由申请人提供)：了解调控和表观遗传策略的分子逻辑，这些策略控制全基因组对调控信号、发育和疾病的转录反应模式，仍然是一个关键的、尚未解决的问题。在此基础上，我们研究了辅活化子和辅阻遏子的转录程序的整合，确定了它们在通过DMA结合转录因子调节基因转录中的作用，并确定了特定的辅阻遏子复合体成分在辅因子交换中的关键作用。依赖辅阻遏子的泛素化/19S蛋白小体机制的招募在基因激活中具有意想不到的作用，PARP1作为一个传感器将特定的信号通路与转录反应程序联系起来。以垂体腺发育为模型的研究使得这些原理的体内表征成为可能，并证明了细胞类型的指定是通过相反的信号梯度在重叠模式中诱导的特定相互作用的转录因子的协同作用实现的。在这次竞争性更新中，我们将重点使用一种新开发的全基因组定位分析方法来探索转录激活程序的基因调控和表观遗传控制的新方面。我们将探索发育过程中基因调控的特定表观遗传策略，以及边界元件功能的分子机制。特定的基因激活程序出人意料地需要特定的组蛋白去甲基酶的作用的假设将被测试，并将探索潜在的分子机制。在发现PARP1的传感功能的基础上，我们将研究一种假设，即多聚ADP-核糖聚合酶在核受体依赖的基因激活中发挥作用的基本策略包括依赖拓扑异构酶的DNA缺口和激活PARP1的酶作用，以从特定的核小体中去除组蛋白H1。我们将以Pit1基因调控为模型，探讨Lef/TCF独立的B-连环蛋白在细胞谱系决定与增殖事件中作用的一个新方面。这些方法结合了基因组学、遗传学和分子生物学的方法，为调控基因表达和器官发生的分子机制提供了新的见解，并将为协调基因反应程序的分子策略提供具体的见解。

DESCRIPTION (provided by applicant): Understanding the molecular logic of regulatory and epigenetic strategies that control genome-wide patterns of transcriptional response to regulatory signals, development and disease remains a key, unresolved issue. Under this Grant, we have investigated the integration of transcriptional programs by coactivators and corepressors, establishing their role in regulated gene transcription by DMA binding transcription factors, and also established the critical role of specific corepressor complex components in cofactor exchange in ligand- dependent gene activation. An unexpected role of a corepressor dependent recruitment of ubiquitylation/19S proteosome machinery in gene activation, and PARP1 as a sensor for linking specific signaling pathway to programs of transcriptional response have been discovered. Investigation of pituitary gland development as a model has permitted the in vivo characterization of these principles, and the demonstration that cell-type specification is achieved by synergistic actions of specific interacting transcription factors induced in overlapping patterns by opposing signaling gradients. In this competitive renewal, we will focus on the use of a newly-developed genome-wide location analysis method to explore the novel aspects of gene regulation and epigenetic control of transcriptional activation programs. We will explore specific epigenetic strategies of gene regulation during development and the molecular mechanisms underlying boundary element function. The hypothesis that specific gene activation programs unexpectedly require the actions of specific histone demethylases will be tested, and the underlying molecular mechanisms will be explored. Based on the discovery of the sensor function of PARP1, we will investigate the hypothesis that the basic strategy by which poly (ADP-ribose) polymerase functions in nuclear receptor-dependent gene activation involves topoisomerase-dependent DNA nicking with activation of PARP1 enzymatic action to dismiss histone H1 from a specific nucleosome. A novel aspect of LEF/TCF independent B-catenin function in cell lineage determination versus proliferation events will be explored using Pit1 gene regulation as a model. These approaches combine genomics, genetic and molecular biological approaches, providing novel insights into aspects of molecular mechanisms of regulated gene expression and organogenesis, and will provide specific insights into the molecular strategies underlying coordinated programs of gene response.