Dynamics of transcriptional regulatory complexes: Mechanism and function

该项目将为基因表达的动态调控提供一种新的机制。基因的开启或关闭是通过基因附近DNA上的“调节蛋白机器”的组装来实现的。这种机器由基因特异性的蛋白质组合组成，这些蛋白质作为一个单元，以特定的方式在特定的细胞中打开或关闭基因。新出现的结果表明，机制已经进化到主动拆卸这些机器，导致机器制造和故障的动态过程。该项目将研究这些调节蛋白机器的动态如何改变特定基因的表达模式。这项研究很重要，因为基因表达模式长期以来被认为仅仅由调控机器的组成来指定，而没有考虑机器构建和破坏的动力学所起的作用。这项工作的结果将定义参与调控机制动力学的因素，以及它们如何选择性地调节基因表达模式。值得注意的是，这项研究计划是一个杰出的女科学家的职业规划、发展和独立进步的组成部分，为构思、执行和管理一个原创的、有影响力的研究项目提供了宝贵的经验。本项目将以糖皮质激素受体（GR）为重点，验证转录调控复合体（TRC）动态是特定基因表达的决定因素的假设。控制GR活性的类固醇激素皮质醇，其循环水平根据昼夜节律和超昼夜（约1小时）周期而波动，并在某些外部信号的响应下达到峰值。dna结合的含gr的TRCs在体内是高度动态的，由分子伴侣驱动分解。本项目将1)定义GR机制：DNA动力学；2)确定将伴侣蛋白定位到TRCs的因素；3)确定TRC动态对gr调控转录的影响。机制将在体外和培养细胞中使用分子生物学，生物化学和蛋白质组学方法来确定伴侣介导的动力学如何在响应糖皮质激素波动时赋予特定的转录模式。揭示动力学作为一种调节模式将促进对环境特异性后生动物基因表达的理解，这是区分细胞类型和形成生物过程的主要机制。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will define a new mechanism for dynamic regulation of gene expression. Turning a gene on or off is known to occur by assembly of a "regulatory protein machine" on the DNA near the gene. Such machines are composed of gene-specific combinations of proteins that work as a unit to switch the gene on or off in particular cells in particular ways. Emerging results indicate that mechanisms have evolved to actively disassemble these machines, resulting in a dynamic process of machine building and breakdown. This project will investigate how the dynamics of these regulatory protein machines alters the expression patterns of specific genes. The study is important because gene expression patterns have long been thought to be specified solely by the makeup of the regulatory machines without considering the role played by dynamics of machine building and breakdown. The results of this work will define factors involved in regulatory machinery dynamics and how they selectively modulate gene expression patterns. Notably, this research plan is integral to the career planning, development, and advancement to independence of an outstanding woman scientist, providing valuable experience in conceiving, executing and managing an original, impactful research program.Focusing on the glucocorticoid receptor (GR), this project will test the hypothesis that transcriptional regulatory complex (TRC) dynamics is a determinant of specific gene expression. The steroid hormone cortisol, which gates GR activity, circulates at levels that fluctuate according to circadian and ultradian (~1 hour) cycles, and spike in response to certain external cues. DNA-bound GR-containing TRCs are highly dynamic in vivo, with disassembly driven by molecular chaperones. This project will 1) define mechanisms of GR:DNA dynamics; 2) identify factors that target chaperones to TRCs to confer disassembly; and 3) determine effects of TRC dynamics on GR-regulated transcription. Mechanisms will be pursued in vitro and in cultured cells using molecular biological, biochemical, and proteomic methods to define how chaperone-mediated dynamics confers specific transcription patterns in response to glucocorticoid fluctuations. Revealing dynamics as a regulatory modality will advance understanding of context-specific metazoan gene expression, the principle mechanism that distinguishes cells types and shapes biological processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.