AH RECEPTOR SIGNALING MECHANISM

描述：（改编自研究者摘要）二恶英是一种氯化多环芳烃，是剧毒的环境污染物，可在商业和自然环境中产生。已知这些物质是强效的啮齿动物致癌物和疑似的人类致癌物。这类试剂最著名的原型是2,3,7,8-四氯二苯并-对二恶英（TCDD）。有充分的证据表明，大多数（如果不是全部）TCDD效应是通过Ah受体（AHR）介导的。因此，为了更好地了解二恶英的作用机制，研究者建议利用过表达的AHR和ARNT蛋白来研究AHR信号通路的分子机制。研究者的工作假设如下：在配体结合后，AHR发生构象变化，导致一些AHR-蛋白相互作用的改变，从而导致一系列生物事件的发生。除了AHR-蛋白相互作用外，涉及ARNT和其他蛋白的其他相互作用也有助于二恶英在AHR介导下的作用。本研究旨在研究AHR信号通路中涉及的蛋白因子和arnt相关蛋白。这些研究不仅为进一步研究AHR介导的PAH作用提供了重要的信息和试剂，而且还通过了解AHR信号通路中涉及的其他蛋白质，为AHR如何调节其靶基因提供了机制见解。提出了三个具体目标：目标1)杆状病毒表达人AHR的纯化和功能表征；目的2)鉴定和表征AHR和ARNT （Ah受体核转运体）功能所需的蛋白因子；目的3)利用Far-Western blot分析研究ARNT相关蛋白。

DESCRIPTION: (Adapted from the Investigator's Abstract) Dioxins, generated both commercially and naturally, are chlorinated polycyclic aromatic hydrocarbons that are highly toxic environmental contaminants. These agents are known to be potent rodent carcinogens and suspected human carcinogens. The best known prototype of this group of agents is 2,3,7,8-tetrachlorodibenzo-p- dioxin (TCDD). It has been well-documented that most, if not all, of the TCDD effects are mediated through the Ah receptor (AHR). Thus, in an effort to better understand the mechanism of dioxin action, the investigator proposes to investigate the molecular mechanism of the AHR signaling pathway using the overexpressed AHR and ARNT proteins. The investigator's working hypothesis is as follows: Upon ligand binding, the AHR undergoes conformational changes resulting in alteration of a number of AHR-protein interactions, which subsequently leads to a cascade of biologic events to occur. In addition to AHR-protein interactions, other interactions involving ARNT and other proteins also contribute to the action of dioxins mediated by the AHR. This proposal contains specific aims investigating the protein factors and ARNT-associated proteins involved in the AHR signaling pathway. Not only do these studies provide important information and reagents to further the study of the PAH action mediated by the AHR, but they also provide mechanistic insights on how the AHR regulates its target genes by understanding what other proteins are involved in the AHR signaling pathway. Three specific aims have been proposed: Aim 1) purification and functional characterization of baculovirus expressed human AHR; Aim 2) identification and characterization of protein factors required for AHR and ARNT (Ah receptor nuclear translocator) function and Aim 3) investigation of ARNT-associated protein using Far-Western blot analysis.