Apoptosis Regulation by Adenovirus and Cellular Genes

描述(申请人提供)：在病毒感染的细胞中，细胞凋亡过程作为一种细胞防御机制来限制病毒的复制和发病。人腺病毒(Ad)感染导致上皮细胞的生产性感染，而淋巴细胞的感染则导致静止性感染。对Ad感染的上皮细胞的研究已经揭示了Ad凋亡程序中的几个关键调控事件，但许多重要的检查点仍有待阐明。E1a癌基因的活性通过与细胞周期调节蛋白的相互作用调节细胞周期，并促进病毒复制，也是感染细胞开始凋亡的原因。E1B-19K蛋白是vBCL-2家族蛋白中的一员，在抑制细胞凋亡中起主导作用。目前的更新建议将研究病毒基因如何在上皮细胞模型中调节核心细胞凋亡机制。目的1鉴定哪些BH3-Only Bcl2家族效应蛋白在腺病毒感染过程中被激活，并确定其在病毒诱导的细胞凋亡中的作用。目的2研究E1B-19K的抗凋亡活性与BH123家族蛋白BAK和Bax形成复合体之间的关系。这一目的还将调查N末端加工形式的Bax是否参与了Ad诱导的细胞凋亡的放大。目的3将研究E1B-19K对细胞质靶向形式的p53的直接凋亡活性的调节。目的探讨多种半胱氨酸天冬氨酸氨基转移酶和凋亡核酸内切酶在Ad诱导的细胞凋亡中的作用。我们的研究将采用遗传和生化方法相结合的方法来确定在Ad诱导的细胞凋亡中的关键调控步骤。我们提出的研究将增加我们对病毒基因EIA和E1B-19K调节细胞内Bcl-2家族基因活性的机制的理解，并确定干预病毒凋亡范式的潜在靶点。

DESCRIPTION (provided by applicant): In virus-infected cells, the process of apoptosis serves as a cellular defense mechanism to restrict viral replication and pathogenesis. Infection with human adenoviruses (Ad) results in productive infection of epithelial cells while infection of lymphoid cells results in quiescent infection. Studies on Ad-infected epithelial cells have revealed several key regulatory events of the Ad apoptosis program, but many important checkpoints remain to be illuminated. The activities of the E1A oncogene that modulate the cell cycle through interaction with cell cycle regulatory proteins and facilitate viral replication also contribute to the onset of apoptosis in infected cells. The E1B-19K protein, a member of the vBCL-2 family proteins plays a dominant role in suppression of apoptosis. This present renewal proposal will investigate how viral genes modulate the core cellular apoptotic machinery in epithelial cell models. Aim 1 will identify which of the BH3-only Bcl-2 family effector proteins is activated during Ad-infection and establish its role in virus-induced apoptosis. Aim 2 will investigate the link between the anti-apoptotic activity of E1B-19K and complex formation with BH123 family proteins BAK and BAX. This aim will also investigate if an N-terminally processed form of BAX is involved in amplification of Ad-induced apoptosis. Aim 3 will study modulation of a direct apoptotic activity of the cytoplasmically targeted form of p53 by E1B-19K. Aim 4 will investigate the role of various caspases and apoptotic endonucleases in Ad-induced apoptosis. Our studies would employ a combination of genetic and biochemical approaches to identify the critical regulatory steps in Ad-induced apoptosis. Our proposed studies will increase our understanding of the mechanism by which viral genes EIA and E1B-19K modulate the activities of cellular Bcl-2 family genes and identify potential targets for intervention in the viral apoptosis paradigm.