ARNT ISOFORMS FROM ONCORHYNCHUS MYKISS

描述：（改编自研究者摘要） 碳氢化合物受体（AHR）和芳香烃受体核 转运蛋白（ARNT）被认为是介导许多的影响， 卤代芳烃。 虽然AHR介导的许多方面 已经在哺乳动物系统中阐明了信号转导系统， 在过去的十年中，该机制仍然存在许多问题， 四氯二苯并对二恶英和相关同系物介导毒性/生物效应， 参与该通路的各种蛋白质的功能。 在 此外，对参与的蛋白质只有适度的了解， 非哺乳动物系统中AHR介导的信号转导。 开始获得 为了深入了解这些问题，该实验室最近分离出了 来自虹鳟鱼的cDNA编码两种具有同源性的新蛋白 到哺乳动物的ARNT。 重要的是，结果表明，（I）多个ARNT 在虹鳟鱼中产生转录本;（ii）多个 转录物可以通过选择性RNA剪接产生，（iii）转录物可以通过选择性RNA剪接产生， 由两种信息表达的蛋白质在AHR介导的 信号转导和（iv）功能的变化可能与 存在不同的COOH末端结构域。 有四个相互关联的 本提案的具体目标侧重于假设分析 选择性RNA剪接导致多种ARNT的表达， 对AHR介导的信号起正或负作用的蛋白质 转导 目的1为虹鳟的分子生物学特性研究 mykiss Arnt基因，以确定可变剪接的程度。 目标二是 确定不同的COOH末端结构域的机制， 虹鳟ARNT亚型在AHR依赖性和非依赖性中的功能 途径。 目的三是建立稳定表达虹鳟的细胞系 mykiss ARNT同种型用于TCDD依赖性和 体内独立基因表达。 目标4是确定空间和 rtARNT信息和蛋白在特定组织中的时间表达 虹鳟和发育过程中。 虹鳟的用途 将提供一个更好的理解的基本意义， ARNT、其演变及其对依赖TCDD和独立TCDD的发展的贡献 参与细胞功能的机制 小说研究的相关性 最近的研究强调了ARNT的功能， 这是一个独立于AHR的功能。 此外，详细研究 ARNT的功能、表达和调控尚未完成， 任何物种。

DESCRIPTION: (Adapted from the Investigator's Abstract) The aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor nuclear translocator (ARNT) protein are thought to mediate many of the effects of halogenated aromatic hydrocarbons. While many aspects of AHR-mediated signal transduction system have been elucidated in mammalian systems over the past decade there are still numerous questions concerning the mechanism whereby TCDD and related congeners mediate toxic/biological effects and the function of the various proteins that contribute to the pathway. In addition, there is only a modest understanding of the proteins involved in AHR-mediated signal transduction in nonmammalian systems. To begin to gain insight into some of these issues, this laboratory has recently isolated cDNAs from Oncorhynchus mykiss that encode two novel proteins with homology to mammalian ARNT. Importantly, the results show that, (I) multiple ARNT transcripts are generated in Oncorhynchus mykiss; (ii) the multiple transcripts may be produced by alternative RNA splicing, (iii) that the proteins expressed from two messages have opposite functions in AHR-mediated signal transduction and (iv) that the change in function may be related to presence of distinct COOH-terminal domains. There are four interrelated specific aims in this proposal that focus on the analysis of the hypothesis that alternative RNA splicing results in the expression of multiple ARNT proteins that can act positively or negatively on AHR-mediated signal transduction. Aim 1 is the molecular characterization of the Oncorhynchus mykiss Arnt gene to determine the extent of alternate splicing. Aim 2 is to determine the mechanism whereby the distinct COOH-terminal domains of Oncorhynchus mykiss ARNT isoforms function in AHR-dependent and independent pathways. Aim 3 is to develop stable cell lines expressing Oncorhynchus mykiss ARNT isoforms for functional analysis of TCDD-dependent and independent gene expression in vivo. Aim 4 is to determine the spatial and temporal expression of rtARNT messages and proteins in specific tissues of Oncorhynchus mykiss and during development. The use of Oncorhynchus mykiss will provide a greater understanding of the fundamental significance of ARNT, its evolution and its contribution to TCDD-dependent and independent mechanisms involved in cellular function. The relevance of novel studies of ARNT function are highlighted by recent studies that clearly show ARNT function that is independent of the AHR. Additionally, a detailed study of the function, expression and regulation of ARNT has not been completed in any species.