Female parasitoid wasps normally inject virulence factors together with eggs into their host to counter host immunity defenses. A newly identified RhoGAP protein in the venom of Microplitis mediator compromises the cellular immunity of its host, Helicoverpa armigera. RhoGAP1 proteins entered H. armigera hemocytes, and the host cellular cytoskeleton was disrupted. Depletion of MmGAP1 by injection of dsRNA or antibody increased the wasp egg encapsulation rate. An immunoprecipitation assay of overexpressed MmGAP1 protein in a Helicoverpa cell line showed that MmGAP1 interacts with many cellular cytoskeleton associated proteins as well as Rho GTPases. A yeast two-hybrid and a pull-down assay demonstrated that MmGAP1 interacts with H. armigera RhoA and Cdc42. These results show that the RhoGAP protein in M. mediator can destroy the H. armigera hemocyte cellular cytoskeleton, restrain host cellular immune defense, and increase the probability of successful parasitism.

雌性寄生蜂通常将毒力因子连同卵一起注入宿主以对抗宿主免疫防御。Microplitis介质毒液中新发现的 RhoGAP 蛋白会损害其宿主棉铃虫的细胞免疫。RhoGAP1 蛋白进入棉铃虫血细胞，宿主细胞骨架被破坏。通过注射 dsRNA 或抗体消耗 MmGAP1 增加了黄蜂卵的包裹率。Helicoverpa细胞系中过表达的 MmGAP1 蛋白的免疫沉淀分析表明，MmGAP1 与许多细胞骨架相关蛋白以及 Rho GTPase 相互作用。酵母双杂交和下拉测定表明 MmGAP1 与棉铃虫RhoA 和 Cdc42。这些结果表明，在RhoGAP蛋白质M.调解员可破坏棉铃虫血细胞细胞骨架，抑制宿主细胞免疫防御，并增加成功寄生的概率。