Molecular mechanism of Androgen Receptor mediated transcription

摘要 转录因子是基因表达的关键决定因素。亲脂性激素配体和伴随的 共调节分子触发转录因子的活性，包括核激素的成员 受体（NR）家族。AR及其剪接变体AR-V7是在前列腺癌发展中起关键作用的NR， 尤其是CRPC。目前靶向AR的疗法主要集中在其配体结合结构域（LBD）， 在AR-V7中不存在。最初对这些疗法有反应的患者在几分钟内就会对它们产生耐药性 年AR和AR-V7都必须招募CoR才能发挥功能。AR-CoR接口中断 抑制雄激素依赖性细胞和CRPC细胞中的AR活性。因此，了解AR变异 与特异性CoR相互作用形成转录活性复合物对于治疗剂的设计至关重要 针对AR和AR-V7我们的初步研究提供了活性NR-CoR的第一个结构理解 复杂的组装，并证明构象变异性对NR介导的 转录激活 在这个提议中，我们假设AR及其变体具有一组共同的CoR，但是组装和 AR复合物中这些CoR的三维排列对每一种都是独特的，并有助于 转录活性的调节。我们建议利用调查人员的互补专长， NR生物学、cryoEM和图像处理以确定转录活性AR的结构基础 配合物我们将通过两个具体目标来实现这一目标：1）解决高分辨率DNA-AR结构， 详细鉴定结构域-结构域相互作用，然后将其与DNA-AR-V7的结构进行比较;以及2）改进 AR-CoR复合物结构的解析，以识别详细的相互作用并确定结构 与AR-V7-CoR复合物相比，这两个目标都将利用cryoEM来可视化功能性AR- CoR复合物。拟议的工作是有意义的，因为结构将描述整体的相互作用， 该系统用于确定哪些组分应该被靶向用于治疗调节。结构 了解AR如何形成功能性二聚体并与CoRs相互作用以激活基因表达， 提供有关转录生物学的关键信息，并使未来的研究能够寻找小的- 分子抑制剂可以影响AR复合物的排列。拟议的多学科工作具有创新性 因为它采用了先进的成像技术，以实现前所未有的洞察结构， AR-CoR复合物、AR异二聚体和靶向它们的药物的功能。

Abstract Transcription factors are key determinants of gene expression. Lipophilic hormonal ligands and accompanying co-regulatory molecules trigger the activity of transcription factors, including members of the nuclear hormone receptor (NR) family. AR and its splice variant AR-V7 are NRs that play key roles in prostate cancer development, and particularly CRPC. Current therapies targeting AR mainly focus on its ligand-binding domain (LBD), which is not present in AR-V7. Patients that respond initially to those therapies become resistant to them within a few years. Both AR and AR-V7 must recruit CoRs to be functionally active. Disruption of the AR–CoR interface inhibits AR activity in both androgen-dependent cells and CRPC cells. Therefore, knowledge of how AR variants interact with specific CoRs to form a transcriptionally active complex is critical for the design of therapeutics targeting AR and AR-V7. Our preliminary studies provided the first structural understanding of active NR–CoR complex assembly and demonstrated that conformational variability has a profound impact on NR-mediated transcriptional activation. In this proposal, we hypothesize that AR and its variants have a common set of CoRs, but that the assembly and three-dimensional arrangement of those CoRs in AR complexes are unique to each and contribute to the regulation of transcriptional activities. We propose to leverage the complementary expertise of investigators in NR biology, cryoEM, and image processing to determine the structural basis of transcriptionally active AR complexes. We will pursue that goal through two specific aims: 1) Solve a high-resolution DNA–AR structure to identify domain-domain interactions in detail and then compare it to the structure of DNA–AR-V7; and 2) Improve the resolution of AR–CoR complexes structures to identify detailed interactions and determine the structural differences in comparison with AR-V7–CoR complexes. Both aims will utilize cryoEM to visualize functional AR– CoR complexes. The proposed work is significant because the structures will describe the overall interactions in the system to determine which components should be targeted for therapeutic modulation. A structural understanding of how AR forms functional dimers and interacts with CoRs to activates gene expression will provide critical information about the biology of transcription and enable future studies of looking for small- molecular inhibitors can affect the AR complex arrangement. The proposed multidisciplinary work is innovative because it employs advanced imaging techniques to achieve unprecedented insights into the structure and function of AR–CoR complexes, AR heterodimers, and the drugs that target them.