REGULATION OF VIRUS-INDUCED PROGRAMMED CELL DEATH

程序性细胞死亡，或称细胞凋亡，是一种内在的、信号诱导的过程，细胞通过这种过程自毁。它是一种高度 对正常发育、组织动态平衡和病原体消除至关重要的调节机制- 被感染的细胞。在人类中，失控的程序性细胞死亡与肿瘤的发生、神经退行性变有关 疾病、免疫缺陷和病毒致病机制。尽管许多进化上保守的细胞成分 死亡途径已经确定，参与细胞凋亡调控的分子机制仍然是 很大程度上是未知的。由于宿主细胞的凋亡可以限制病毒的繁殖，许多病毒进化出了不同的策略。 调节细胞死亡途径。介导这种病毒干预的蛋白质为我们提供了对 细胞死亡程序。这项提议的长期目标是确定细胞凋亡的分子机制 是通过研究三种杆状病毒编码的凋亡调节因子：P35，P49和IAP来调节的。我们的方法 重点是利用杆状病毒感染的昆虫细胞作为一种强大而方便的系统来进行分子分析 诱导和抑制细胞凋亡。基于细胞凋亡领域的最新进展，我们使用集成 用生物化学、遗传学和细胞生物学的方法确定P49和IAP抗肿瘤的分子机制 细胞凋亡活性。我们重点研究了p49‘S抑制抗pancaspase抑制剂的启动子caspase的新能力 P35通过定义两种不可逆抑制物对caspase选择性的分子决定因素。利用最近的 发现杆状病毒能有效地向培养的黑腹果蝇运送凋亡调节剂 细胞中，我们确定了P49和P35的体内靶点，并定义了该模式生物中的caspase级联。我们 确定病毒IAP抗细胞凋亡活性的分子机制 混合型IAP和细胞凋亡效应因子。同时，我们还研究了其功能意义 使用新的显性负抑制物对病毒和细胞IAP进行齐聚。总而言之，这些 预计研究将提供有关病毒-宿主相互作用和调控的新的基本信息 动物的程序性细胞死亡。这些知识将有助于制定治疗策略 细胞凋亡相关疾病。

Programmed cell death, or apoptosis, is a built-in, signal-induced process by which a cell self-destructs. It is a highly regulated mechanism that is critical for normal development, tissue homeostasis, and the elimination of pathogen- infected cells. In humans, misregulated programmed cell death is associated with tumorigenesis, neurodegenerative diseases, immunodeficiency, and viral pathogenesis. Although many evolutionarily conserved components of the cell death pathway have been identified, the molecular mechanisms involved in cellular regulation of apoptosis are still largely unknown. Since host cell apoptosis can limit virus multiplication, many viruses have evolved diverse strategies to regulate the cell death pathway. The proteins that mediate such viral intervention have provided key insight into the cell death program. The long term objective of this proposal is to define the molecular mechanisms by which apoptosis is regulated through the study of three baculovirus-encoded apoptotic regulators: P35, P49, and IAP. Our approach focuses on the use of baculovirus-infected insect cells as a powerful yet convenient system for molecular analysis of both the induction and suppression of apoptosis. Building on recent advances in the apoptosis field, we use integrated approaches in biochemistry, genetics, and cell biology to determine the molecular mechanism of P49 and IAP anti- apoptotic activity. We focus on P49's novel ability to inhibit an initiator caspase resistant to the pancaspase inhibitor P35 by defining the molecular determinants of caspase selectivity by both irreversible inhibitors. Utilizing the recently discovered capacity of baculoviruses to efficiently deliver apoptotic regulators to cultured Drosophila melanogaster cells, we identify the in vivo targets of P49 and P35 and define the caspase cascade in this model organism. We determine the molecular mechanism of virus IAP anti-apoptotic activity by characterizing the interactions between hybrid IAPs and cellular apoptotic effectors. In concert, we also investigate the functional significance of oligomerization for both viral and cellular IAPs by using novel dominant negative inhibitors. Collectively, these studies are expected to provide new and fundamental information on virus-host interactions and the regulation of programmed cell death in animals. Such knowledge will contribute to the development of therapeutic strategies for apoptosis-associated diseases.