THYROID/RETINOIC ACID RECEPTOR INTERACTING PROTEINS

甲状腺/视黄酸受体相互作用蛋白

• 批准号: 6532910
• 负责人: MUKUL MATHUR
• 金额: $ 11.05万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-16 至 2005-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6532910
• 关键词: DNA binding protein; HeLa cells; RNA binding protein; RNA splicing; SDS polyacrylamide gel electrophoresis; gel mobility shift assay; gene induction /repression; nuclear receptors; oncogenes; polymerase chain reaction; protein protein interaction; protein structure; retinoid binding proteins; thyroid hormones; transcription factor; western blottings; yeast two hybrid system

The long term goal of this project is to determine the mechanism of gene regulation by nuclear receptors. We aim to focus mainly on Thyroid and Rednoid X Receptors as they are known to heterodimerize and form stable complexes with DNA response elements. DNA bound nuclear receptors associate with protein complexes that may either repress or activate the transcription through mechanisms that are not completely understood. Our aim is to isolate and characterize the novel interacting cofactors and to understand its functional and physiological relevance. To achieve this goal we have taken a biochemical approach to isolate and purify receptor interacting proteins on affinity columns. Large scale purification has allowed us to characterize three major proteins interacting with DNA binding domain of these receptors. The 65 kDa protein is a RNA binding protein TLS, that was originally identified as part of a fusion protein associated with human myxoid liposarcoma. The 105 kDa protein is a splicing factor known as PSF (PTB associated splicing factor). This protein is highly homologous to the third receptor interacting protein with a molecular weight of 50 kDa and is identified as NonO, also an RNA binding protein. PSF and NonO are components of a heterodimer and both genes have been reported in translocation involving a helix loop helix transcription factor gene, TFE3. In each case the fusion of almost the entire reading frame of PSF/NonO to TFE3 DBD results in renal cell carcinoma. Thus, the three RNA binding proteins that interact with nuclear receptors also turn into an oncogene when fused to a transcription factor and brought to an active transcription site. Our major goal will be to study the role of these protein factors in modulating the function of TR and RXR. These studies will also shed light on the possible mechanism by which PSF, NonO and TLS turn into oncogenes when fused to a transcription factor. The association of splicing factors with nuclear receptors that also participate in causing sarcomas when fused to a transcription factor is a novel and very interesting observation. Splicing factors might be playing a dual role through their functionally distinct domains and this study will provide evidences that transcription, RNA processing and oncogenecity might be intimately connected nuclear processes. We will also specify the region on the DNA binding domain of these receptors where these three proteins interact.

该项目的长期目标是确定核受体调节基因调节的机制。 我们的目标是主要集中在甲状腺和染色体X受体上，因为它们众所周知它们具有与DNA响应元件的异构二聚体并形成稳定的复合物。 DNA结合的核受体与蛋白质复合物相关，可以通过未完全理解的机制抑制或激活转录。 我们的目的是隔离和表征新颖的相互作用辅助因子，并了解其功能和生理相关性。 为了实现这一目标，我们采用了生化方法来隔离和纯化受体相互作用的蛋白质在亲和力柱上。大规模纯化使我们能够表征三种与这些受体的DNA结合结构域相互作用的主要蛋白质。 65 kDa蛋白是一种RNA结合蛋白TLS，最初被鉴定为与人粒细胞脂肪肉瘤相关的融合蛋白的一部分。 105 kDa蛋白是称为PSF（PTB相关剪接因子）的剪接因子。 该蛋白与第三受体相互作用的蛋白质高度同源，分子量为50 kDa，也被鉴定为Nono，也是RNA结合蛋白。 PSF和NONO是异二聚体的成分，并且已经报道了涉及螺旋环螺旋转录因子基因TFE3的易位。 在每种情况下，PSF/NONO与TFE3 DBD的几乎整个阅读框的融合会导致肾细胞癌。因此，与核受体相互作用的三种RNA结合蛋白在融合到转录因子并带到活性转录位点时也会变成癌基因。我们的主要目标是研究这些蛋白质因子在调节TR和RXR功能中的作用。 这些研究还将阐明PSF，NONO和TLS与转录因子融合时变成癌基因的可能机制。与转录因子融合时，剪接因子与核受体的关联是一种新颖而有趣的观察结果。剪接因子可能通过其功能不同的领域发挥双重作用，这项研究将提供证据表明，转录，RNA处理和癌性可能是密切相关的核过程。 我们还将在这些受体的DNA结合结构域上指定这三种蛋白相互作用的区域。