Insect Molecular Genetics and Biotechnology Group, Institute of Biology, National Centre for Scientific Research Demokritos, Neapoleos & Patr. Grigoriou, 153 10 Aghia Paraskevi Attikis, Athens, Greece.
Insect Biochem Mol Biol. 2011 Dec;41(12):993-1002. doi: 10.1016/j.ibmb.2011.09.008. Epub 2011 Oct 14.
In the tripartite parasitization system of the lepidopteran host Manduca sexta, the endoparasitoid wasp Cotesia congregata and its endosymbiotic virus, C. congregata Bracovirus (CcBV), the expression of viral proteins is necessary for successful parasitization. Here we have examined the in vitro effects of six members of the ankyrin-repeat protein family (Ank) of CcBV, which are thought to interfere with the host's induced innate immune responses, on the transcriptional activity of a heterologous lepidopteran Rel/NFκB transcription factor, Relish1 of Bombyx mori. Using as transcriptional activator BmRelish1-d2 (R1d2), a constitutively active mutant of the major regulator of the Imd pathway, BmRelish1, in conjunction with a reporter gene controlled by a B. mori antimicrobial peptide gene promoter, we have found that 5 of the 6 examined Anks suppress R1d2-dependent transcriptional activity to various degrees. Immunofluorescence studies have also revealed that while some of the Ank proteins have a rather strict cytoplasmic localization, others are detected both in the cytoplasm and the nucleus of the expressing cells and that colocalization with R1d2 occurs exclusively in the nucleus. Thus, our results suggest that functional and spatial differences among the various CcBV Ank family members may be responsible for the observed differential inhibition of R1d2 activity.
在鳞翅目宿主烟青虫的三方寄生系统中，内寄生蜂舞毒蛾长尾小蜂及其共生病毒舞毒蛾长尾小蜂多粒包埋病毒（CcBV），病毒蛋白的表达对于成功寄生是必要的。在这里，我们研究了 CcBV 的ankyrin 重复蛋白家族（Ank）的六个成员在体外对异源鳞翅目 Rel/NFκB 转录因子，家蚕 Relish1 的转录活性的影响。我们使用作为转录激活剂的家蚕 Relish1-d2（R1d2），即 Imd 途径主要调控因子家蚕 Relish1 的组成活性突变体，以及由家蚕抗菌肽基因启动子控制的报告基因，发现 6 个被检测到的 Anks 中的 5 个以不同程度抑制了 R1d2 依赖性转录活性。免疫荧光研究还表明，虽然一些 Ank 蛋白具有严格的细胞质定位，但其他蛋白既存在于细胞质中，也存在于表达细胞的细胞核中，并且仅在细胞核中与 R1d2 发生共定位。因此，我们的结果表明，不同的 CcBV Ank 家族成员之间的功能和空间差异可能是导致观察到的 R1d2 活性抑制差异的原因。
