Fujiyuki Tomoko, Takeuchi Hideaki, Ono Masato, Ohka Seii, Sasaki Tetsuhiko, Nomoto Akio, Kubo Takeo
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
J Virol. 2004 Feb;78(3):1093-100. doi: 10.1128/jvi.78.3.1093-1100.2004.
To identify candidate genes involved in the aggressive behavior of worker honeybees, we used the differential display method to search for RNAs exclusively detected in the brains of aggressive workers that had attacked a hornet. We identified a novel, 10,152-nucleotide RNA, termed Kakugo RNA. Kakugo RNA encodes a protein of 2,893 amino acid residues that shares structural features and sequence similarities with various picorna-like virus polyproteins, especially those from sacbrood virus, which infects honeybees. The Kakugo protein contains several domains that correspond to the virion protein, helicase, protease, and RNA-dependent RNA polymerase domains of various picorna-like virus polyproteins. When the worker bee tissue lysate was subjected to sucrose density gradient centrifugation, Kakugo RNA, except for the material at the bottom, was separated into two major peaks. One of the peaks corresponded to the position of Kakugo mRNA, and the other corresponded to the position of the poliovirus virion. These results suggest that the Kakugo RNA exists as an mRNA-like free RNA and virion RNA in the honeybee. Furthermore, injection of the lysate supernatant from the attacker heads into the heads of noninfected bees resulted in a marked increase in Kakugo RNA. These results demonstrate that Kakugo RNA is a plus-strand RNA of a novel picorna-like virus and that the brains of aggressive workers are infected by this novel virus. Kakugo RNA was detected in aggressive workers but not in nurse bees or foragers. In aggressive workers, Kakugo RNA was detected in the brain but not in the thorax or abdomen, indicating a close relation between viral infection in the brain and aggressive worker behaviors.
为了鉴定与工蜂攻击行为相关的候选基因，我们采用差异显示法，寻找仅在攻击过黄蜂的攻击性工蜂大脑中检测到的RNA。我们鉴定出一种新的、10152个核苷酸的RNA，称为警觉RNA（Kakugo RNA）。警觉RNA编码一种含有2893个氨基酸残基的蛋白质，该蛋白质与各种类微小核糖核酸病毒多聚蛋白具有结构特征和序列相似性，尤其是与感染蜜蜂的囊状幼虫病毒的多聚蛋白。警觉蛋白包含几个结构域，分别对应于各种类微小核糖核酸病毒多聚蛋白的病毒粒子蛋白、解旋酶、蛋白酶和RNA依赖性RNA聚合酶结构域。当对工蜂组织裂解物进行蔗糖密度梯度离心时，除了底部的物质外，警觉RNA被分离成两个主要峰。其中一个峰对应于警觉mRNA的位置，另一个峰对应于脊髓灰质炎病毒粒子的位置。这些结果表明，警觉RNA在蜜蜂中以类似mRNA的游离RNA和病毒粒子RNA的形式存在。此外，将攻击者头部的裂解物上清液注射到未感染蜜蜂的头部，导致警觉RNA显著增加。这些结果证明，警觉RNA是一种新型类微小核糖核酸病毒的正链RNA，且攻击性工蜂的大脑被这种新型病毒感染。在攻击性工蜂中检测到了警觉RNA，但在哺育蜂或采集蜂中未检测到。在攻击性工蜂中，警觉RNA在大脑中被检测到，但在胸部或腹部未被检测到，这表明大脑中的病毒感染与工蜂的攻击行为之间存在密切关系。
