Vaccinia virus E2L null mutants exhibit a major reduction in extracellular virion formation and virus spread
Vaccinia virus E2L null mutants exhibit a major reduction in extracellular virion formation and virus spread
复制标题
DOI：
10.1128/jvi.00037-08
复制
发表时间：
2008-05-01
影响因子：
5.4
通讯作者：
Moss, Bernard
中科院分区：
文献类型：
--
作者：
Domi, Arban;Weisberg, Andrea S.;Moss, Bernard
痘苗病毒 E2L (VACWR058) 基因在所有已测序的脊索痘病毒中都是保守的，预计编码 86 kDa 的蛋白质，没有可识别的功能基序或非痘病毒同源物。尽管紧邻开放阅读框上游的区域缺乏最佳共有启动子基序，但 E2 蛋白的表达发生在病毒 DNA 复制后。然而，转染研究表明，与充分表征的中间和晚期启动子相比，该启动子较弱。 E2蛋白存在于从感染细胞中纯化的成熟病毒粒子中，但以细胞外包膜形式更丰富。尽管脊索痘病毒中 E2L 基因是保守的，但可以从牛痘病毒的 WR 和 IHD-J 株中分离出缺失突变体。这些无效突变体在所有测试的细胞系中产生非常小的噬斑，成熟感染性病毒粒子的数量减少，并且细胞外病毒粒子的数量非常低。尽管如此，病毒蛋白质合成在质量和数量上似乎都正常。细胞外病毒形成的缺陷得到了电子显微镜的证实，电子显微镜也显示出池膜包裹病毒体的一些异常。然而，确实形成的细胞外病毒颗粒能够诱导肌动蛋白尾部的形成。
The vaccinia virus E2L (VACWR058) gene is conserved in all sequenced chordopoxviruses and is predicted to encode an 86-kDa protein with no recognizable functional motifs or nonpoxvirus homologs. Although the region immediately upstream of the open reading frame lacked optimal consensus promoter motifs, expression of the E2 protein occurred after viral DNA replication. Transfection studies, however, indicated that the promoter was weak compared to well-characterized intermediate and late promoters. The E2 protein was present in mature virions purified from infected cells but was more abundant in extracellular enveloped forms. Despite the conservation of the E2L gene in chordopoxviruses, deletion mutants could be isolated from both the WR and IHD-J strains of vaccinia virus. These null mutants produced very small plaques in all cell lines tested, reduced amounts of mature infectious virions, and very low numbers of extracellular virions. Nevertheless, viral protein synthesis appeared qualitatively and quantitatively normal. The defect in extracellular virus formation was corroborated by electron microscopy, which also showed some aberration in the wrapping of virions by cisternal membranes. Extracellular virions that did form, however, were able to induce actin tail formation.