The minor capsid protein L2 contributes to two steps in the human papillomavirus type 31 life cycle
The minor capsid protein L2 contributes to two steps in the human papillomavirus type 31 life cycle
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DOI：
10.1128/jvi.79.7.3938-3948.2005
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发表时间：
2005-04-01
影响因子：
5.4
通讯作者：
Lambert, PF
中科院分区：
文献类型：
--
作者：
Holmgren, SC;Patterson, NA;Lambert, PF
先前的研究，这依赖于使用假病毒体产生的异源细胞类型，有时会导致矛盾的结论，乳头瘤病毒，L2，在病毒生命周期中的次要衣壳蛋白的作用。在这项研究中，我们进行了分析与真正的病毒颗粒组装在自然宿主细胞中，以评估L2的作用，在病毒感染的生命周期。在这些研究中，我们使用器官型（筏）培养系统来重现高危型人乳头瘤病毒HPV31的完整病毒生命周期，该病毒为野生型或L2突变型。转染后，L2突变型HPV 31基因组能够在分化差（基底样）的人角质形成细胞的增殖群体中将其自身建立为核质粒，并将其基因组扩增至高拷贝数，支持晚期病毒基因表达，并在已诱导经历终末分化的人角质形成细胞中引起病毒颗粒的形成。这些结果表明，在没有功能性L2的情况下，病毒生命周期的非生产性和生产性阶段都正常发生。然而，在分析产生的病毒颗粒时，我们发现掺入L2缺陷型病毒体的病毒DNA的量减少了约10倍。此外，L2缺陷型病毒的感染性降低超过100倍。由于后者的缺陷不能仅由10倍的减少，我们得出结论，L2有助于至少两个步骤的生产传染性病毒。
Prior studies, which have relied upon the use of pseudovirions generated in heterologous cell types, have led to sometimes conflicting conclusions regarding the role of the minor capsid protein of papillomaviruses, L2, in the viral life cycle. In this study we carry out analyses with true virus particles assembled in the natural host cell to assess L2's role in the viral infectious life cycle. For these studies we used the organotypic (raft) culture system to recapitulate the full viral life cycle of the high-risk human papillomavirus HPV31, which was either wild type or mutant for L2. After transfection, the L2 mutant HPV31 genome was able to establish itself as a nuclear plasmid in proliferating populations of poorly differentiated (basal-like) human keratinocytes and to amplify its genome to high copy number, support late viral gene expression, and cause formation of virus particles in human keratinocytes that had been induced to undergo terminal differentiation. These results indicate that aspects of both the nonproductive and productive phases of the viral life cycle occur normally in the absence of functional L2. However, upon the analysis of the virus particles generated, we found an approximate 10-fold reduction in the amount of viral DNA encapsidated into L2-deficient virions. Furthermore, there was an over-100-fold reduction in the infectivity of L2-deficient virus. Because the latter deficiency cannot be accounted for solely by the 10-fold decrease in encapsidation, we conclude that L2 contributes to at least two steps in the production of infectious virus.