Vaccinia virus A17L gene product is essential for an early step in virion morphogenesis.
Vaccinia virus A17L gene product is essential for an early step in virion morphogenesis.
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痘苗病毒 A17L 基因产物对于病毒颗粒形态发生的早期步骤至关重要。
DOI：
10.1128/jvi.69.8.4640-4648.1995
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Rodriguez,JR
中科院分区：
文献类型：
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作者：
Rodriguez,D;Esteban,M;Rodriguez,JR
痘苗病毒(VV)A17L基因编码一个23 kDa的蛋白，该蛋白被蛋白水解酶切割产生21 kDa的产物，并被整合到病毒颗粒中。我们先前已经证明了21 kDa的蛋白质与VV 14 kDa的包膜蛋白形成了一个稳定的复合体，并暗示21 kDa的蛋白质可能用于将14 kDa的蛋白质锚定到病毒粒子的包膜上(D.Rodríguez，J.R.Rodríguez，和M.Esteban，J.Virol)。67：3435-3440,1993)。为了研究21-kDa蛋白在病毒粒子组装中的作用，在本研究中，我们构建了一个VV重组体VVindA17L，它包含一个受大肠杆菌抑制子/操纵子系统调控的可诱导的A17L基因。在没有诱导剂的情况下，A17L基因的关闭是完全的，这种关闭与病毒产量减少约3个对数单位有关。虽然早期和晚期病毒多肽通常是在没有A17L基因产物的情况下合成的，但在这些条件下，主要的P4a和p4b核心蛋白的蛋白分解过程明显受损。在没有异丙基硫代半乳糖苷(IPTG)的情况下感染的细胞的电子显微镜检查表明，病毒粒子的形态发生在非常早期阶段就完全停止了，甚至在新月形的膜形成之前，新月形的膜是第一个可区分的病毒结构。在不允许的条件下，在感染VVindA17L的细胞质中只能观察到类似于利福平小体的电子致密结构，但没有膜。考虑到Sodeik等人提出的最新组装模型。(B.Sodeik，R.W.Dom，M.Ericsson，G.Hiller，C.E.Machamer，W.van‘t Hof，G.van Meer，B.Moss，and G.Griffiths，J.Cell Biol.121：521-541,1993)，我们认为该蛋白定位于中间隔室，参与这些膜向病毒工厂的募集，在那里它形成特征的新月形结构，随后导致病毒粒子的形成。
Vaccinia virus (VV) A17L gene encodes a 23-kDa protein that is proteolytically cleaved to generate a 21-kDa product that is incorporated into the viral particles. We have previously shown that the 21-kDa protein forms a stable complex with the VV 14-kDa envelope protein and suggested that the 21-kDa protein may serve to anchor the 14-kDa protein to the envelope of the virion (D. Rodríguez, J. R. Rodríguez, and M. Esteban, J. Virol. 67:3435-3440, 1993). To study the role of the 21-kDa protein in virion assembly, in this investigation we generated a VV recombinant, VVindA17L, that contains an inducible A17L gene regulated by the E. coli repressor/operator system. In the absence of the inducer, shutoff of the A17L gene was complete, and this shutoff correlated with a reduction in virus yields of about 3 log units. Although early and late viral polypeptides are normally synthesized in the absence of the A17L gene product, proteolytic processing of the major p4a and p4b core proteins was clearly impaired under these conditions. Electron microscopy examination of cells infected in the absence of isopropylthiogalactopyranoside (IPTG) revealed that virion morphogenesis was completely arrested at a very early stage, even prior to the formation of crescent-shaped membranes, which are the first distinguishable viral structures. Only electron-dense structures similar to rifampin bodies, but devoid of membranes, could be observed in the cytoplasm of cells infected with VVindA17L under nonpermissive conditions. Considering the most recent assembly model presented by Sodeik et al. (B. Sodeik, R. W. Doms, M. Ericsson, G. Hiller, C. E. Machamer, W. van't Hof, G. van Meer, B. Moss, and G. Griffiths, J. Cell Biol. 121:521-541, 1993), we propose that this protein is targeted to the intermediate compartment and is involved in the recruitment of these membranes to the viral factories, where it forms the characteristic crescent structures that subsequently result in the formation of virions.