Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
Arch Virol. 2011 Oct;156(10):1707-15. doi: 10.1007/s00705-011-1039-3. Epub 2011 Jun 5.
To initiate an efficient primary infection, it is important for baculovirus virions to penetrate through the peritrophic membrane (PM) of the host insect. It is frequently reported that enhancins of baculoviruses significantly enhance viral infection by degrading the various protein components of PMs. However, not all baculoviruses encode enhancins. GP37s of baculoviruses share high amino acid identity with fusolins, synergistic factors found in entomopoxviruses. In this study, a truncated Cydia pomonella granulovirus GP37 was expressed in Escherichia coli. The expressed GP37 effectively bound to chitin, and binding occurred predominantly within 3 h. GP37 altered the protein profiles of Spodoptera exigua PMs, from which a 50-kDa protein was dissociated. Droplet-feeding bioassays indicated that GP37 significantly enhanced the infectivity of nucleopolyhedroviruses (NPVs) and the lethality of Bacillus thuringiensis (Bt) in S. exigua larvae. This is the first demonstration of the enhancement of NPVs and Bt infection by a baculovirus GP37.
为了有效地引发初次感染，杆状病毒粒子穿透宿主昆虫的围食膜（PM）非常重要。据频繁报道，杆状病毒的增强因子通过降解 PM 的各种蛋白成分显著增强病毒感染。然而，并非所有杆状病毒都编码增强因子。杆状病毒的 GP37 与昆虫痘病毒中的 fusolins（协同因子）具有高度的氨基酸同一性。在本研究中，在大肠杆菌中表达了截断的 Cydia pomonella 颗粒体病毒 GP37。表达的 GP37 能有效地与几丁质结合，并且结合主要发生在 3 小时内。GP37 改变了斜纹夜蛾 PM 的蛋白图谱，其中 50 kDa 的蛋白被解离。液滴喂养生物测定表明，GP37 显著增强了核多角体病毒（NPV）和苏云金芽孢杆菌（Bt）在斜纹夜蛾幼虫中的感染力。这首次证明了杆状病毒 GP37 增强了 NPV 和 Bt 的感染。
