BEEgroup, Biozentrum, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
Insect Biochem Mol Biol. 2011 Dec;41(12):968-81. doi: 10.1016/j.ibmb.2011.09.006. Epub 2011 Oct 7.
Honeybee populations are severely threatened by parasites and diseases. Recent outbreaks of Colony Collapse Disorder (CCD) has caused loss of more than 35% of bee colonies in the USA, and this is thought to at least in part be due to parasites and/or disease. Interestingly, the honeybee possesses of a limited set of immune genes compared to other insects. Non-canonical immune genes of honeybee are of interest because they may provide greater insights into the peculiar nature of the immune system of this social insect. Previous analyses of bee haemolymph upon bacterial challenge identified a novel leucine-rich repeat protein termed IRP30. Here we show that IRP30 behaves as a typical secreted immune protein. It is expressed simultaneously with carboxylesterase upon treatment with bacteria or other elicitors of immune response. Furthermore we characterize the gene and the mRNA encoding this protein and the IRP30 protein itself. Its regulation and evolution reveal that IRP30 belongs to a protein family, distributed broadly among Hymenoptera, suggesting its ancient function in immune response. We document an interesting case of a recent IRP30 loss in the ant Atta cephalotes and hypothesize that a putative IRP30 homolog of Nasonia emerged by convergent evolution rather than diverged from a common ancestor.
蜜蜂种群受到寄生虫和疾病的严重威胁。最近爆发的蜂群崩溃症（CCD）导致美国超过 35%的蜂群消失，据认为这至少部分是由于寄生虫和/或疾病造成的。有趣的是，与其他昆虫相比，蜜蜂拥有有限数量的免疫基因。蜜蜂的非典型免疫基因很有研究价值，因为它们可能提供更多关于这种社会性昆虫免疫系统独特性质的见解。之前对蜜蜂血淋巴在细菌攻击下的分析鉴定出一种称为 IRP30 的新型富含亮氨酸的重复蛋白。在这里，我们表明 IRP30 表现为一种典型的分泌型免疫蛋白。它与羧酸酯酶同时表达，在受到细菌或其他免疫反应诱导剂处理时表达。此外，我们还对该基因及其编码的 mRNA 进行了特征描述。IRP30 蛋白本身及其调控和进化揭示了它属于一种广泛分布在膜翅目昆虫中的蛋白家族，表明其在免疫反应中的古老功能。我们记录了一个有趣的案例，即 Atta cephalotes 蚂蚁最近失去了 IRP30，并假设一种假定的 Nasonia 的 IRP30 同源物是通过趋同进化而不是从共同祖先分化而来的。
