Studies on the Ah Receptors Signaling Mechanism

商业和自然产生的二恶英是氯化多环芳烃， 是剧毒的环境污染物。众所周知，这些药物是强效的啮齿动物致癌物， 疑似人类致癌物质。这组毒剂最著名的原型是2，3，7，8- 四氯二苯并对二恶英(TCDD)已经很好地记录了TCDD的大部分影响，如果不是全部的话 是通过AH受体(AhR)介导的。为了更好地了解TCDD的发病机制 作用，我们将研究AhR信号通路的分子机制。工作假说 结果如下：TCDD结合后，受体发生核转位，AhR形成 AHR/Arnt/Dre复合体在细胞核内，导致基因转录的激活。我们发现p23 和CyP40在体外促进这种AhR三元复合体的形成(参考文献：1.Shetty，P.V.，Wang，X.， 和Chan W.K.(2004)Arch.生物化学。生物群落。429，42-9；2.Shetty，P.V.，Bhagwat，B.Y.和Chan，W. K.(2003)Biochem.药水。65,941-8)，而这些蛋白似乎影响细胞内的AhR信号 文化研究。本研究重点探讨了p23和CyP40在AhR信号转导中的内源性作用。 提出了四个具体目标如下：我们将使用p23和CyP40击倒和 以确定(1)AhR和Arnt的异二聚化和ArnT的结合 在完整细胞中，DRE的异源二聚体受到p23和CyP40的影响(Aim 1)；AhR的组装 基因转录激活前增强子区的复合体受p23和CyP40的影响 完整细胞(AIM 2)和(3)核AhR的命运受p23和CyP40的影响。我们还将检查 AhR信令中对p23和CyP40的要求(目标4)。删除和突变研究将是 绘制出AhR功能对p23和CyP40的最低结构要求。 CyP40和AhR之间的相互作用将被研究和表征。CyP40-相互作用的蛋白质 对于完整的CyP40对AhR功能的影响是必不可少的，将被识别和表征。

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). In an effort to better understand the mechanism of TCDD action, we will investigate the molecular mechanism of the AhR signaling pathway. The working hypothesis is as follows: Upon TCDD binding, nuclear translocation of the receptor occurs and the AhR forms the AhR/Arnt/DRE complex in the nucleus, leading to activation of gene transcription. We discovered that p23 and CyP40 potentiate the formation of this AhR ternary complex in vitro (Refs: 1. Shetty, P. V., Wang, X., and Chan, W. K. (2004) Arch. Biochem. Biophys. 429, 42-9; 2. Shetty, P. V., Bhagwat, B. Y., and Chan, W. K. (2003) Biochem. Pharmacol. 65, 941-8) and these protein appear to affect the AhR signaling in cell culture studies. This proposal focuses on the endogenous roles of p23 and CyP40 in the AhR signaling. Four specific aims have been proposed as follows: We will use p23 and CyP40 knockdown and overexpressed cells to determine whether (1) the heterodimerization of AhR and Arnt and the binding of the heterodimer to the DRE are affected by p23 and CyP40 in intact cells (Aim 1); the assembly of the AhR complex to the enhancer region prior to activation of gene transcription is affected by p23 and CyP40 in intact cells (Aim 2) and (3) the fate of the nuclear AhR is affected by p23 and CyP40. We will also examine the requirements of p23 and CyP40 in the AhR signaling (Aim 4). Deletion and mutation studies will be performed to map out the minimal structural requirement of p23 and CyP40 for the AhR function. Interactions between CyP40 and AhR will be examined and characterized. CyP40-interacting proteins that are essential for the full CyP40 effect on the AhR function will be identified and characterized.