Slack Jeffrey M, Dougherty Edward M, Lawrence Susan D
United State Department of Agriculture, Agriculture Research Service, Plant Sciences Institute, Insect Biocontrol Laboratory, Bldg 011A, Rm 214, BARC-West, Beltsville, MD 20705-2350, USA1.
J Gen Virol. 2001 Sep;82(Pt 9):2279-2287. doi: 10.1099/0022-1317-82-9-2279.
The Autographa californica multiple nucleopolyhedrovirus (AcMNPV) protein p74 is associated with the occlusion-derived virus (ODV) envelope. p74 is essential for oral infectivity of ODV and has been proposed to play a role in midgut attachment and/or fusion. In this study, p74 protein was expressed in-frame with green fluorescent protein (GFP) to create a p74-GFP chimera. The C-terminal GFP portion of the chimera facilitated visualization of the trafficking of p74 in baculovirus-infected Spodoptera frugiperda (Sf-9) cells. p74-GFP chimeric proteins localized in the intranuclear ring zone of the nucleus and were found to co-precipitate with the microvesicle fraction of cell lysates. A series of truncations of p74 was expressed as p74-GFP chimeras in recombinant baculoviruses. When C-terminal region S580-F645 was deleted from p74, p74-GFP chimera localization became non-specific and chimeras became soluble. p74 region S580-F645 directed GFP to the intranuclear ring zone in a similar pattern to full-length p74. The hydrophobic C terminus of p74 plays a role in protein localization and possibly in transmembrane anchoring and insertion.
苜蓿银纹夜蛾多核型多角体病毒（AcMNPV）蛋白p74与源自包涵体的病毒（ODV）包膜相关。p74对于ODV的口服感染性至关重要，并且有人提出它在中肠附着和/或融合中起作用。在本研究中，p74蛋白与绿色荧光蛋白（GFP）读码框内表达，以创建p74-GFP嵌合体。嵌合体的C末端GFP部分有助于观察杆状病毒感染的草地贪夜蛾（Sf-9）细胞中p74的运输。p74-GFP嵌合蛋白定位于细胞核的核内环区，并发现与细胞裂解物的微囊泡部分共沉淀。一系列p74截短体在重组杆状病毒中表达为p74-GFP嵌合体。当从p74中删除C末端区域S580-F645时，p74-GFP嵌合体的定位变得非特异性，并且嵌合体变得可溶。p74区域S580-F645以与全长p74相似的模式将GFP导向核内环区。p74的疏水C末端在蛋白质定位中起作用，并且可能在跨膜锚定和插入中起作用。
