Mda-5: Novel Apoptosis Inducing Gene

Mda-5：新型细胞凋亡诱导基因

• 批准号: 6919305
• 负责人: PAUL B FISHER
• 金额: $ 29.79万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6919305
• 关键词: RNA; SDS polyacrylamide gel electrophoresis; adenosinetriphosphatase; apoptosis; carcinogenesis; cysteine endopeptidases; enzyme activity; gene expression; growth inhibitors; helicase; immunoprecipitation; mass spectrometry; northern blottings; western blottings

DESCRIPTION (provided by applicant): Interferons (IFN) have broad cell-type specific effects, including growth inhibition, antiviral activity, modulation of differentiation, induction or inhibition of programmed cell death (apoptosis) and regulation of immune system genes and expression. The growth inhibitory and/or apoptotic effects of type I IFNs, which include IFN-alpha and IFN-beta, are mediated by protein kinase R, 2'-5' oligoadenylate syntase and additional IFN-inducible RNases. The RNA helicases comprise a family of proteins implicated in diverse processes of RNA metabolism, including degradation, translation and editing. The relevance of IFN-induced RNA helicases in mediating changes in cellular physiology is not understood. Subtraction hybridization identified melanoma differentiation associated gene-5 (mda-5) as a novel IFN-beta induced gene whose encoded protein contains a caspase recruitment domain (CARD) and RNA helicase motif. Purified MDA-5 fusion protein exhibits dsRNA-dependent ATPase activity and because of the presence of both CARD and RNA helicase domains represents a unique member of the RNA helicase gene family. Moreover, the RNA helicase motif of MDA-5 shares certain peculiarities with growth inhibitory and/or RNase III helicase proteins. These findings, including the growth suppressing activity of mda-5 in mammalian cells, support the hypothesis that MDA-5 is a unique RNA helicase involved in growth inhibitory/apoptotic RNA metabolism elicited by IFN treatment. Since a potential involvement of RNA metabolism in the apoptotic process is unique, analysis of MDA-5, which may represent a molecule that for the first time links these important processes, provides an extraordinary opportunity to define the role of apoptotic RNA metabolism and IFN action. This information could prove relevant in understanding the mechanism of cellular defense conferred by IFN against viral attack as well as the role of interferons in mediating antitumor responses. Experiments will be performed to define the biological role of mda-5 in IFN-induced growth inhibition and/or apoptosis, identify potential protein partners of MDA-5 involved in mediating mda-5 action, and identify RNA substrates of MDA-5 and characterize the ATPase activity of MDA-5. Understanding MDA-5 function could provide significant insights into RNA with novel apoptotic processing potential defining therapeutics delimiting infectivity and pathogenesis. Additionally, based on its chromosomal location, 2q24, the present studies could also shed light on a potential role of mda-5 in specific cancer etiologies as well as enhance our appreciation of the carcinogenic process.

性状（由申请人提供）：干扰素（IFN）具有广泛的细胞类型特异性作用，包括生长抑制、抗病毒活性、分化调节、诱导或抑制程序性细胞死亡（凋亡）以及调节免疫系统基因和表达。I型IFN（包括IFN-α和IFN-β）的生长抑制和/或凋亡作用由蛋白激酶R、2 ′-5 ′寡腺苷酸合酶和另外的IFN诱导型RNA酶介导。RNA解旋酶包括涉及RNA代谢的不同过程（包括降解、翻译和编辑）的蛋白质家族。IFN诱导的RNA解旋酶在介导细胞生理学变化中的相关性尚不清楚。差减杂交技术鉴定出黑色素瘤分化相关基因5（melanoma differentiation associated gene-5，mda-5）是一个新的IFN-β诱导基因，其编码蛋白含有半胱天冬酶募集结构域（caspase recruitment domain，CARD）和RNA解旋酶基序。纯化的MDA-5融合蛋白表现出dsRNA依赖性ATP酶活性，并且由于CARD和RNA解旋酶结构域的存在，代表了RNA解旋酶基因家族的独特成员。此外，MDA-5的RNA解旋酶基序与生长抑制蛋白和/或RNA酶III解旋酶蛋白具有某些特性。这些发现，包括生长抑制活性的mda-5在哺乳动物细胞中，支持的假设，MDA-5是一个独特的RNA解旋酶参与生长抑制/凋亡RNA代谢引起的IFN治疗。由于RNA代谢在凋亡过程中的潜在参与是独特的，MDA-5的分析，这可能是第一次连接这些重要过程的分子，提供了一个非凡的机会来定义凋亡RNA代谢和IFN作用的作用。这些信息可以证明相关的理解IFN对病毒攻击的细胞防御机制，以及干扰素介导的抗肿瘤反应的作用。将进行实验以确定mda-5在IFN诱导的生长抑制和/或细胞凋亡中的生物学作用，鉴定参与介导mda-5作用的MDA-5的潜在蛋白伴侣，鉴定MDA-5的RNA底物并表征MDA-5的ATP酶活性。了解MDA-5的功能可以提供重要的见解RNA与新的细胞凋亡加工潜力定义治疗划定感染性和发病机制。此外，基于其染色体定位，2 q24，目前的研究还可以阐明mda-5在特定癌症病因学中的潜在作用，以及增强我们对致癌过程的理解。