State Key Laboratory of Silkworm Genome Biology, Southwest University, 400716, Chongqing, China; Chongqing Engineering and Technology Research Center for Silk Biomaterials and Regenerative Medicine, 400716, Chongqing, China; Southwest University Engineering Research Center for Cancer Biomedical and Translational Medicine, 400716, Chongqing, China.
State Key Laboratory of Silkworm Genome Biology, Southwest University, 400716, Chongqing, China; Chongqing Engineering and Technology Research Center for Silk Biomaterials and Regenerative Medicine, 400716, Chongqing, China; Southwest University Engineering Research Center for Cancer Biomedical and Translational Medicine, 400716, Chongqing, China.
Dev Comp Immunol. 2019 May;94:66-72. doi: 10.1016/j.dci.2019.01.014. Epub 2019 Feb 1.
Broad-Complex Z2 (Br-C Z2) is an ecdysone inducible transcription factor that regulates physiological, innate immune and developmental events in insects. Here, we identified an orthologue of Br-C Z2 from silkworm, Bombyx mori (BmBr-C Z2) to study its involvement in immune responses. The quantitative real-time PCR analysis revealed that BmBr-C Z2 was expressed ubiquitously in all tested tissues under normal physiological conditions. Further, developmental profile displayed that BmBr-C Z2 expression was detectable in different developmental stages, however the gene's expression was highest in the molting and pre-pupal stages. Administration of 20-hydroxyecdysone (20E) enhanced the expression levels of BmBr-C Z2 in hemocytes. The challenge with pathogens and pathogen associated molecular patterns (PAMPs) also upregulated the mRNA levels of BmBr-C Z2 in hemocytes when compared with the control. By contrast, the ectopic expression of BmBr-C Z2 remarkably increased the production of antimicrobial peptides, while the knock-down of this gene by double stranded RNA decreased their production. Dual-luciferase assay exhibited that BmBr-C Z2 induced the expression of lysozyme by directly binding to its promoter region. The treatment of Escherichia coli following the knock-down of BmBr-C Z2 strongly reduced the survival rate of silkworm larvae. These results suggest that BmBr-C Z2 plays an important biological role in the innate immune responses of silkworm by regulating immune-related genes.
宽复合体 Z2（Br-C Z2）是一种蜕皮激素诱导的转录因子，可调节昆虫的生理、先天免疫和发育事件。在这里，我们从家蚕（Bombyx mori）中鉴定出 Br-C Z2 的同源物（BmBr-C Z2），以研究其在免疫反应中的作用。定量实时 PCR 分析显示，BmBr-C Z2 在正常生理条件下在所有测试组织中均广泛表达。此外，发育谱显示 BmBr-C Z2 的表达在不同的发育阶段均可检测到，但其表达在蜕皮和预蛹阶段最高。20-羟基蜕皮酮（20E）的给药增强了血细胞中 BmBr-C Z2 的表达水平。与对照相比，病原体和病原体相关分子模式（PAMPs）的挑战也上调了血细胞中 BmBr-C Z2 的 mRNA 水平。相比之下，BmBr-C Z2 的异位表达显着增加了抗菌肽的产生，而该基因的双链 RNA 敲低则降低了它们的产生。双荧光素酶测定显示，BmBr-C Z2 通过直接结合其启动子区域诱导溶菌酶的表达。BmBr-C Z2 敲低后大肠杆菌的处理强烈降低了家蚕幼虫的存活率。这些结果表明，BmBr-C Z2 通过调节免疫相关基因在家蚕的先天免疫反应中发挥重要的生物学作用。
