Prion Cycle Regulation In Vivo

体内朊病毒循环调节

• 批准号: 7031895
• 负责人: TRICIA R. SERIO
• 金额: $ 28.97万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7031895
• 关键词: Saccharomyces cerevisiae; cell cycle; centrifugation; chemical kinetics; chimeric proteins; conformation; enzyme activity; fluorescence resonance energy transfer; gene expression; genetic regulatory element; genetic strain; immunoprecipitation; microorganism reproduction; molecular assembly /self assembly; molecular chaperones; phenotype; prions; protein biosynthesis; protein protein interaction; protein structure function; transcription factor; transfection /expression vector; virus replication

DESCRIPTION (provided by applicant): Recent advances suggest that self-replication of protein physical states directs both the development and spread of the Transmissible Spongiform Encephalopathies and the inheritance of some phenotypic traits in lower eukaryotes. This novel biological process, known as the prion hypothesis, predicts that a unique group of proteins has the capacity to adopt multiple conformational states with distinct physiological consequences in vivo. Since one-fold-one-function proteins are unable to act in roles that have historically been linked to nucleic acids such as infectivity and inheritance, understanding how a prion protein's structure can be constrained to allow the faithful propagation of associated phenotypes but remain sufficiently flexible to allow occasional transitions in state is crucial to understanding the physiological consequences of the protein- only hypothesis. The prion cycles of lower eukaryotes provide experimentally tractable model systems for studying prion cycle regulation in vivo. For example, the Sup35 protein of S. cerevisiae is a component of the translation termination complex whose function is reversibly modulated by a prion cycle. In the non-prion state, Sup35 facilitates efficient termination (psi- phenotype), but in the prion form, Sup35's activity is compromised leading to stop codon read-through ([PSI+] phenotype). While the [PSI+] and [psi-] phenotypes are largely stable, they spontaneous interconvert (about 1 cell/million) and can be induced to quantitatively switch by chemical and molecular stimuli. Using this system, we will begin to elucidate the molecular mechanism underlying the near-faithful propagation of prion forms in vivo by focusing on two contributing factors: the interplay of distinct forms when present in the same cell and the trans regulators of efficient prion conversion. Toward this end, we will 1) determine the molecular basis of prion variant dominance in vivo, 2) elucidate the molecular mechanisms by which known regulators of the Sup35/[PSI+] prion cycle modulate propagation and phenotypic transitions, and 3) screen for and characterize novel prion regulators. Together, these lines of investigation will build a framework for understanding protein-only phenotypic propagation in terms of prion protein biogenesis. A strong foundation of previous work indicates that the knowledge gleaned from prion studies in lower eukaryotes is clearly and directly applicable to our understanding of prion mechanisms and their physiological consequences in mammals.

描述（由申请人提供）：最近的进步表明，蛋白质物理状态的自我复制指导了可透射的海绵状脑病的发育和传播，以及在下层真核生物中某些表型特征的遗传。这种新型的生物学过程被称为王室假设，预测一组独特的蛋白质具有在体内具有不同生理后果的多种构象状态的能力。由于一双功能蛋白无法用历史上与核酸（例如感染性和遗传性）相关的角色作用，因此了解如何限制prion蛋白的结构以允许相关表型的忠实传播，但仍然足够柔韧性，以允许在状态中偶然过渡到蛋白质的影响。较低真核生物的prion周期为研究体内的prion循环调节提供了实验性的模型系统。例如，酿酒酵母的Sup35蛋白是翻译终止络合物的组成部分，其功能可通过prion循环可逆地调节。在非统治状态下，SUP35促进了有效的终止（PSI-表型），但在prion形式中，Sup35的活性受到损害，导致停止密码子读取（[PSI+]表型）。尽管[PSI+]和[PSI-]表型基本稳定，但它们自发互连（约1个单元/百万），可以通过化学和分子刺激来定量切换。使用该系统，我们将开始阐明体内近乎信仰传播的分子机制，通过关注两个因素：当同一细胞中存在不同形式的相互作用和有效的prion prion conversion依的反式调节剂时，不同形式的相互作用。为此，我们将1）确定体内prion变体优势的分子基础，2）阐明了Sup35/[PSI+] Prion循环的已知调节剂调节传播和表型过渡的已知调节剂的分子机制，以及3）筛选和表征和表征新的新型Prion Prion调节器。总之，这些研究线将建立一个框架，以理解仅蛋白质表型传播的prion蛋白生物发生。以前的工作的强大基础表明，下层真核生物中的幼虫研究中收集的知识显然是我们对哺乳动物中的prion机制及其生理后果的理解。