Jiangsu University of Science and Technology, Zhenjiang, 212018, Jiangsu, China.
Arch Virol. 2018 Oct;163(10):2719-2725. doi: 10.1007/s00705-018-3912-9. Epub 2018 Jun 13.
Bombyx mori larvae exhibit in vivo defensive reactions immediately after invasion by a virus. One of these defense systems is to express appropriate microRNAs (miRNAs) to respond to the infection. A novel Bombyx mori-encoded miRNA, bmo-miR-390, was identified previously by high-throughput sequencing. Based on bioinformatic predictions, the Bombyx mori nuclear polyhedrosis virus cg30 gene (BmNPV-cg30) is one of the target genes of bmo-miR-390. In this study, expression vectors with an enhanced green fluorescence protein (EGFP) or a luciferase (luc) reporter gene together with bm-miR-390 or the cg30 3' UTR were constructed and used to co-transfect BmN cells. Using a dual luciferase reporter (DLR) assay, we found that bmo-miR-390 significantly downregulates the expression of BmNPV-cg30 (P < 0.05) in vitro. Moreover, artificially synthesized bmo-miR-390 mimics enhanced the regulatory effect of bmo-miR-390, while an inhibitor eliminated the inhibitory effect. These results show for the first time that bmo-miR-390 can effectively downregulate the expression of BmNPV-cg30 in BmNPV-infected BmN cells.
家蚕幼虫在病毒入侵后立即表现出体内防御反应。其中一种防御系统是表达适当的 microRNA（miRNA）来应对感染。先前通过高通量测序鉴定了一种新型家蚕编码 miRNA，bmo-miR-390。根据生物信息学预测，家蚕核多角体病毒 cg30 基因（BmNPV-cg30）是 bmo-miR-390 的靶基因之一。在这项研究中，构建了带有增强型绿色荧光蛋白（EGFP）或荧光素酶（luc）报告基因的表达载体，并与 bm-miR-390 或 cg30 3'UTR 一起转染 BmN 细胞。使用双荧光素酶报告（DLR）测定法，我们发现 bmo-miR-390 显著下调了体外 BmNPV-cg30 的表达（P<0.05）。此外，人工合成的 bmo-miR-390 模拟物增强了 bmo-miR-390 的调节作用，而抑制剂则消除了抑制作用。这些结果首次表明 bmo-miR-390 可以有效下调 BmNPV 感染的 BmN 细胞中 BmNPV-cg30 的表达。
