Mechanisms of regulation of apoptosis by HSV genes

描述(申请人提供)：单纯疱疹病毒(HSV) 数量惊人的功能旨在阻止宿主对 感染。被HSV阻止的功能列表中包括编程单元 由病毒基因产物的特定功能或由外源引起的死亡 药物(Fas配体、肿瘤坏死因子、热休克或渗透性休克等)。 具体地说，在缺少几种基因病毒产物之一的情况下，HSV 感染在其感染过程中多步骤诱导细胞凋亡 复制循环。程序性细胞死亡的诱导和途径都可能 依赖于细胞类型。本申请中描述的建议书基于 三个关键观察：(I)缺乏糖蛋白D(GD)的病毒突变体诱导 细胞凋亡。Gd对突变体诱导的细胞凋亡的阻断作用 Gd或GJ在杆状病毒载体中的表达(Ii)突变人， D120缺乏编码主要调节蛋白ICP4的基因，导致 所有被测试的细胞系均发生了细胞凋亡。正在进行的研究表明，细胞凋亡 是由ICPO诱导的，这是一种在感染D120的人中过度表达的混杂反式激活因子 细胞。在D120突变感染细胞中制造的ICPO与野生型ICP0的不同之处在于 有几处房产。D120突变体诱导的细胞凋亡在细胞中被阻断 Bcl2的过度表达也独立于病毒蛋白激酶US3。(Iii) 细胞含有DFF40的复合体(一种负责碎裂的DNA酶 细胞DNA)和DFF45(其抑制物)。在诱导细胞凋亡中 外源性物质，释放细胞色素C，激活caspase，DFF45是 分裂，细胞DNA被降解。在感染野生型病毒的细胞中 在渗透性休克的诱导下，caspase被激活，但DFF45受到保护 从乳沟。US3蛋白激酶似乎参与了阻断 DFF45的切割。本申请书所建议的研究目标 是(I)确定GD病毒诱导细胞凋亡和 GD或GJ阻止它的手段；(Ii)确定ICP0的机制 诱导细胞凋亡及US3阻断细胞凋亡的有效靶点(III) 阐明单纯疱疹病毒阻断DFF45裂解和阻止 细胞DNA片段化。

DESCRIPTION (provided by applicant): Herpes simplex viruses (HSV) encode a surprisingly high number of functions designed to thwart host responses to infection. Included in the list of function blocked by HSV are programmed cell death induced both by specific functions of viral gene products or by exogenous agents (Fas ligand, tumor necrosis factor, thermal or osmotic shock, etc). Specifically, in the absence of one of several gene viral products, HSV infection results in induction of apoptosis at multiple steps during its replicative cycle. Both the induction and pathway of programmed cell death may be cell type-dependent. The proposal described in this application is based on three key observations: (i) Virus mutants lacking glycoprotein D (gD) induce apoptosis. Apoptosis induced by gD about mutants is blocked independently by expression of gD or gJ delivered in trans bybaculovirus vectors. (ii) A mutant, d120 lacking the gene encoding ICP4, the major regulatory protein, induces apoptosis in all cell lines tested. Studies in progress indicate that apoptosis is induced by ICPO, a promiscuous transactivator overexpressed in d120-infected cells. ICPO made in d120 mutant-infected cells differs from wild type ICP0 in several properties. Apoptosis induced by the d120 mutant is blocked in cells overexpressing Bcl-2 and also independently by viral protein kinase Us3. (iii) Cells contain a complex of DFF40 (a DNase responsible for fragmentation of cellular DNA) and DFF45 (its inhibitor). In cells induced to apoptosis by exogenous agents, cytochrome C is released, caspases are activated, DFF45 is cleaved, and cellular DNA is degraded. In cells infected with wild-type virus and induced by osmotic shock, caspases are activated but DFF45 is protected from cleavage. The Us3 protein kinase appears to be involved in blocking cleavage of DFF45. The objectives of the studies proposed in this application are (i) to determine the mechanisms by which gD- viruses induce apoptosis and the means by which gD or gJ block it; (ii) to defme the mechanism by which ICP0 induces apoptosis and the effective target of Us3 in blocking it (iii) to elucidate the mechanism by which HSV blocks the cleavage of DFF45 and precludes fragmentation of cellular DNA.