Kroemer Jeremy A, Webb Bruce A
University of Kentucky, Department of Entomology, S-225 Agricultural Sciences Center North, Lexington, KY 40546, USA.
J Virol. 2006 Dec;80(24):12219-28. doi: 10.1128/JVI.01187-06. Epub 2006 Sep 27.
Ichnoviruses (IVs) occur in obligate symbiotic associations with endoparasitic ichneumonid wasps. IVs are injected with eggs during parasitization, where viral infection and gene expression alter host physiology to ensure endoparasitoid survival. The seven Campoletis sonorensis IV (CsIV) vankyrin genes encode proteins that possess ankyrin repeat domains resembling the inhibitory domains of NF-kappaB transcription factor inhibitors (IkappaBs). The CsIV vankyrins are divided into two subclasses: those expressed primarily in the host fat body (three genes) and those expressed in host hemocytes (four genes). CsIV vankyrin proteins showed limited antigenic similarity when analyzed by Western blotting. Cellular localization and expression patterns of recombinant vankyrin proteins in High Five and Sf9 insect cells differed within and between the subclasses and in cells exposed to lipopolysaccharide, laminarin, or viral immune challenge. In unstimulated Sf9 cells, five vankyrins were detected in cell nuclei. The remaining two proteins localized predominantly to cytoplasmic granules. Immune stimulation of cells resulted in a nuclear-to-cytoplasmic shift of three vankyrins but did not affect localization of other variants. When expressed from recombinant Autographa californica multiple nucleopolyhedroviruses (AcMNPVs), all vankyrins showed a nuclear localization during early stages of infection with patterns resembling those of immune-challenged cells as the infection progressed. Two fat body vankyrins also produced unique biological effects when expressed from recombinant AcMNPV. Insect cells infected with these viruses exhibited enhanced longevity compared to those infected with viruses expressing other vankyrins. Together, these data suggest that vankyrin proteins in CsIV have divergent physiological functions.
昆虫病毒（IVs）与内寄生姬蜂形成专性共生关系。在寄生过程中，IVs会随卵注入，病毒感染和基因表达会改变宿主生理机能，以确保内寄生蜂的存活。七种索诺拉黄足飞蝗泥蜂IV（CsIV）泛素蛋白基因编码的蛋白质具有锚蛋白重复结构域，类似于核因子κB转录因子抑制剂（IkappaBs）的抑制结构域。CsIV泛素蛋白分为两个亚类：主要在宿主脂肪体中表达的（三个基因）和在宿主血细胞中表达的（四个基因）。通过蛋白质印迹分析，CsIV泛素蛋白显示出有限的抗原相似性。重组泛素蛋白在High Five和Sf9昆虫细胞中的细胞定位和表达模式在亚类内部和之间以及在暴露于脂多糖、海带多糖或病毒免疫挑战的细胞中有所不同。在未受刺激的Sf9细胞中，在细胞核中检测到五种泛素蛋白。其余两种蛋白主要定位于细胞质颗粒。细胞的免疫刺激导致三种泛素蛋白从细胞核转移到细胞质，但不影响其他变体的定位。当从重组苜蓿银纹夜蛾多核型多角体病毒（AcMNPVs）表达时，所有泛素蛋白在感染早期均显示出核定位，随着感染的进展，其模式类似于免疫挑战细胞。当从重组AcMNPV表达时，两种脂肪体泛素蛋白也产生了独特的生物学效应。与感染表达其他泛素蛋白的病毒的昆虫细胞相比，感染这些病毒的昆虫细胞寿命延长。总之，这些数据表明CsIV中的泛素蛋白具有不同的生理功能。
