Cell surface events of human papillomavirus type 16 and 18 infection

描述（由申请人提供）：人乳头瘤病毒（HPV）形成一个大的病毒家族，其中一些与各种形式的癌症有关，包括宫颈癌。它们诱发了全世界7%以上的女性癌症。特别是，由于缺乏癌症筛查计划，HPV对世界上不发达地区的妇女构成负担。这项研究的长期目标是了解HPV感染的早期事件，重点是细胞表面发生的事件。HPV 16型的主要衣壳蛋白L1主要负责病毒与存在于细胞表面和细胞外基质（ECM）上的硫酸乙酰肝素蛋白聚糖（HSPG）的初始结合。附着到HSPG诱导L1和次要衣壳蛋白L2的构象发生变化，我们现在可以用单克隆抗体检测到这两者。X射线结构分析与X。Chen鉴定了病毒衣壳上的几个HSPG结合位点。我们的初步数据表明，它们的顺序使用在初级连接和二级结合事件，以及诱导构象转变。此外，我们收集的证据表明，亲环素B（CyPB）在HPV感染过程中参与了两个不同的步骤：介导细胞表面L2构象变化和促进病毒基因组的脱壳。目的1将测试我们的假设，即病毒衣壳上的两个HS结合位点在HPV感染的细胞表面事件期间被顺序使用。这将通过HS结合位点的结构指导诱变来实现。目的二是利用siRNA敲除和小分子抑制剂结合生物化学和细胞生物学方法研究亲环素在HPV感染中的作用。目的3是致力于了解潜在的过程中的构象变化影响两种衣壳蛋白的分子细节。详细了解这些事件将允许开发干预策略来对抗HPV诱导的恶性病变。

DESCRIPTION (provided by applicant): Human papillomaviruses (HPV) form a large family of viruses some of which are associated with various forms of cancer, including cervical carcinoma. They induce more than seven per cent of all cancers in women worldwide. Especially, HPV pose a burden to women in underdeveloped regions in the world due to a lack of access to cancer screening programs. The long term goal of this research is to understand early events of HPV infection with the focus on events occurring on the cell surface. The major capsid protein, L1, of HPV type 16 is primarily responsible for initial binding of virus to heparan sulfate proteoglycan (HSPG) present on cell surface and extracellular matrix (ECM). Attachment to HSPG induces a shift in the conformation of L1 and the minor capsid protein, L2, both of which we can now detect with monoclonal antibodies. X-ray structure analysis in collaboration with X. Chen identified several HSPG binding sites on the viral capsid. Our preliminary data suggest their sequential use in primary attachment and secondary binding events as well for inducing conformational shifts. In addition, we collected evidence for an involvement of Cyclophilin B (CyPB) in two distinct steps during HPV infection: mediating L2 conformational changes on the cell surface and facilitating uncoating of the viral genome. Aim 1 will test our hypothesis that two HS binding sites on the viral capsid are sequentially used during cell surface events of HPV infection. This will be achieved by a structure-guided mutagenesis of HS binding sites. Aim 2 is intended to delineate the function of Cyclophilins in HPV infection using siRNA knock down and small molecule inhibitors combined with biochemical and cell biological approaches. Aim 3 is dedicated to understand the processes underlying the conformational shifts affecting both capsid proteins in molecular detail. Understanding these events in detail will allow the development of interfering strategies to fight HPV-induced malignant lesions.