Epstein-Barr virus transforming protein LMP1 plays a critical role in virus production
Epstein-Barr virus transforming protein LMP1 plays a critical role in virus production
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DOI：
10.1128/jvi.79.7.4415-4424.2005
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发表时间：
2005-04-01
影响因子：
5.4
通讯作者：
Takada, K
中科院分区：
文献类型：
--
作者：
Ahsan, N;Kanda, T;Takada, K
EB病毒潜伏膜蛋白I(LMP1)是EB病毒诱导B细胞转化的关键分子，在病毒复制的溶解周期中也有大量表达。然而，这种强烈的LMP1诱导的生物学意义仍不清楚。我们设计了一个包含Akata株EBV整个基因组的细菌人工染色体克隆，以特异性地破坏LMP1基因。建立了携带LMP1缺失EBV表型的AKATA细胞克隆，研究了LMP1缺失对病毒产生的影响。我们发现病毒DNA扩增程度和病毒晚期基因产物的表达水平不受LMP1缺失的影响，表明LMP1缺失的EBV与野生型EBV一样有效地进入裂解复制周期。我们的电子显微镜观察证实了这一点，即使在没有LMP1的情况下，也会在细胞核内形成核衣壳。相反，LMP1的缺失严重损害了病毒向培养上清液的释放，导致感染效率低下。截短的LMP1在含有LMP1缺失EBV的Akata细胞中的表达挽救了病毒释放到培养上清液和感染性，全长LMP1部分挽救了感染性。这些结果表明，LMP1在病毒裂解周期中的可诱导表达在病毒生产中起着关键作用。
The Epstein,Barr virus (EBV) latent membrane protein I (LMP1), which is critical for EBV-induced B-cell transformation, is also abundantly expressed during the lytic cycle of viral replication. However, the biological significance of this strong LMP1 induction remains unknown. We engineered a bacterial artificial chromosome clone containing the entire genome of Akata strain EBV to specifically disrupt the LMP1 gene. Akata cell clones harboring the episomes of LMP1-deleted EBV were established, and the effect of LMP1 loss on virus production was investigated. We found that the degree of viral DNA amplification and the expression levels of viral late gene products were unaffected by LMP1 loss, demonstrating that the LMP1-deleted EBV entered the lytic replication cycle as efficiently as the wild-type counterpart. This was confirmed by our electron microscopic observation that nucleocapsid formation inside nuclei occurred even in the absence of LMP1. By contrast, loss of LMP1 severely impaired virus release into culture supernatants, resulting in poor infection efficiency. The expression of truncated LMP1 in Akata cells harboring LMP1-deleted EBV rescued the virus release into the culture supernatant and the infectivity, and full-length LMP1 partially rescued the infectivity. These results indicate that inducible expression of LMP1 during the viral lytic cycle plays a critical role in virus production.