State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.
Front Immunol. 2018 Oct 23;9:2301. doi: 10.3389/fimmu.2018.02301. eCollection 2018.
Parasitoid wasps depend on a variety of maternal virulence factors to ensure successful parasitism. Encapsulation response carried out by host hemocytes is one of the major host immune responses toward limiting endoparasitoid wasp offspring production. We found that VRF1, a metalloprotease homolog venom protein identified from the endoparasitoid wasp, , could modulate egg encapsulation in its host, the cotton bollworm, . Here, we show that the VRF1 proenzyme is cleaved after parasitism, and that the C-terminal fragment containing the catalytic domain enters host hemocytes 6 h post-parasitism. Furthermore, using yeast two-hybrid and pull-down assays, VRF1 is shown to interact with the NF-κB factor, Dorsal. We also show that overexpressed of VRF1 in an cell line cleaved Dorsal . Taken together, our results have revealed a novel mechanism by which a component of endoparasitoid wasp venom interferes with the Toll signaling pathway in the host hemocytes.
寄生蜂依赖多种母体毒力因子来确保成功寄生。宿主血细胞执行的包被反应是宿主限制内寄生蜂后代产生的主要宿主免疫反应之一。我们发现，VRF1 是一种金属蛋白酶同源毒液蛋白，它可以调节其宿主棉铃虫的卵包被。在这里，我们表明，VRF1 前酶在寄生后被切割，并且含有催化结构域的 C 末端片段在寄生后 6 小时进入宿主血细胞。此外，使用酵母双杂交和下拉测定，表明 VRF1 与 NF-κB 因子 Dorsal 相互作用。我们还表明，在 细胞系中过表达 VRF1 可切割 Dorsal。总之，我们的结果揭示了内寄生蜂毒液的一种成分干扰宿主血细胞中的 Toll 信号通路的新机制。
