A novel baculovirus envelope fusion protein with a proprotein convertase cleavage site
A novel baculovirus envelope fusion protein with a proprotein convertase cleavage site
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DOI：
10.1006/viro.2000.0483
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发表时间：
2000-09-15
期刊：
影响因子：
3.7
通讯作者：
Zuidema, D
中科院分区：
文献类型：
--
作者：
IJkel, WFJ;Westenberg, M;Zuidema, D
研究了甜菜夜蛾核型多角体病毒（Spodoptera exigua multicapsid nucleopolyhedrovirus，SeMNPV）进入培养细胞的机制。SeMNPV出芽病毒（BV）通过内吞作用进入，如组I NPV、苜蓿银纹夜蛾（Ac）MNPV和假杉毒蛾（Op）MNPV的BV一样。在I组NPV中，在感染后，内体的酸化触发病毒和内体膜的融合，这由BV包膜糖蛋白GP 64介导。然而，SeMNPV基因组缺乏GP 64包膜融合蛋白（EFP）的同源物。在SeMNPV ORF 8（Se 8; 76 kDa）中鉴定了OpMNPV GP 64 EFP的功能同源物，并且似乎是主要的BV包膜蛋白。令人惊讶的是，该蛋白的60-kDa切割产物存在于BV包膜中。一个弗林蛋白酶样前蛋白转化酶切割位点（R-X-WR-R）被鉴定为紧接在成熟Se 8蛋白的N-末端的上游，并且该位点在舞毒蛾（Ld）MNPV Se 8同源物（Ld 130）中也是保守的。合胞体形成分析表明，单独的海和Ld 130足以介导膜融合后，酸化的培养基。Se 8和Ld 130的C-末端GFP融合蛋白主要定位于昆虫细胞的质膜。这与它们的融合活性一致，并支持See基因产物是GP 64 EFP的功能同源物的结论。(C)北京大学出版社.
The entry mechanism of Spodoptera exigua multicapsid nucleopolyhedrovirus (SeMNPV), a group II NPV, in cultured cells was examined. SeMNPV budded virus (BV) enters by endocytosis as do the BVs of the group I NPVs, Autographa californica (Ac) MNPV and Orgyia pseodotsugata (Op) MNPV. in group I NPVs, upon infection acidification of the endosome triggers fusion of the viral and endosomal membrane, which is mediated by the BV envelope glycoprotein GP64. However, the SeMNPV genome lacks a homolog of GP64 envelope fusion protein (EFP). A functional homolog of the OpMNPV GP64 EFP was identified in SeMNPV ORF8 (Se8; 76 kDa) and appeared to be the major BV envelope protein. Surprisingly, a 60-kDa cleavage product of this protein is present in the BV envelope. A furin-like proprotein convertase cleavage site (R-X-WR-R) was identified immediately upstream of the N-terminus of the mature Se8 protein and this site was also conserved in the Lymantria dispar (Ld) MNPV homolog (Ld130) of Se8. Syncytium formation assays showed that sea and Ld130 alone were sufficient to mediate membrane fusion upon acidification of the medium. Furthermore, C-terminal GFP-fusion proteins of Se8 and Ld130 were primarily localized in the plasma membrane of insect cells. This is consistent with their fusogenic activity and supports the conclusion that the See gene product is a functional homolog of the GP64 EFP. (C) 2000 Academic Press.