Yu Fei, Wang Longlong, Wang Hao, Sheng Jialu, Lu Liqun
National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai, P. R. China.
Key Laboratory of Agriculture Ministry for Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Shanghai, P. R. China.
Oncotarget. 2017 Aug 17;8(42):71500-71511. doi: 10.18632/oncotarget.20309. eCollection 2017 Sep 22.
SUMOylation, a post-translational modification, is involved in interaction between hosts and viruses, and participates in diverse cellular processes including inflammatory responses and innate immunity. Here, we investigated the interaction between reovirus infection and the cellular SUMOylation machinery using grass carp reovirus (GCRV) as a model. Full-length cDNAs of grass carp SUMO-1 and SUMO-2 were obtained and phylogenetic analysis indicated that they shared high homology with those of higher vertebrates. The two modifiers and SUMO conjugating enzyme 9 (Ubc9) were ubiquitously expressed in all tested tissues of grass carp. During GCRV infection in CIK cells, transcriptional expressions of SUMO1/2 and Ubc9 were significantly inhibited; while UV-inactivated GCRV failed to inhibit the expression of the three molecules, which suggested that SUMOylation system was suppressed during viral replication. In CIK cells treated with inhibitor 2-D08 for SUMOylation, GCRV replication was not interfered; however, transcriptional analysis of immune genes involved in anti-viral interferon (IFN) response indicated that IRF2 and PKR were significantly up-regulated in CIK cells treated with inhibitor in contrast to IRF1, IRF7 and IFNI. Furthermore, 2-D08 treatment coupled with GCRV challenge resulted in higher IRF2 and PKR level during infection in comparison to those of CIK cells infected with GCRV only. These results indicated that inhibition of SUMOylation should result in the induction of PKR via IFN-independent manner, and both IFN-signaling and IFN-independent signaling seemed to involve in the upregulation of PKR during the process of GCRV infection. Repression of SUMOylation by GCRV might represent a cellular antiviral mechanism.
小泛素样修饰（SUMOylation）是一种翻译后修饰，参与宿主与病毒之间的相互作用，并参与包括炎症反应和固有免疫在内的多种细胞过程。在此，我们以草鱼呼肠孤病毒（GCRV）为模型，研究呼肠孤病毒感染与细胞SUMOylation机制之间的相互作用。获得了草鱼SUMO-1和SUMO-2的全长cDNA，系统发育分析表明它们与高等脊椎动物的SUMO-1和SUMO-2具有高度同源性。这两种修饰因子和SUMO缀合酶9（Ubc9）在草鱼所有检测组织中均普遍表达。在CIK细胞感染GCRV期间，SUMO1/2和Ubc9的转录表达显著受到抑制；而紫外线灭活的GCRV未能抑制这三种分子的表达，这表明在病毒复制过程中SUMOylation系统受到抑制。在用SUMOylation抑制剂2-D08处理的CIK细胞中，GCRV复制未受到干扰；然而，参与抗病毒干扰素（IFN）反应的免疫基因的转录分析表明，与IRF1、IRF7和IFNI相比，在用抑制剂处理的CIK细胞中IRF2和PKR显著上调。此外，与仅感染GCRV的CIK细胞相比，2-D08处理联合GCRV攻击导致感染期间IRF2和PKR水平更高。这些结果表明，SUMOylation的抑制应以不依赖IFN的方式导致PKR的诱导，并且在GCRV感染过程中IFN信号传导和不依赖IFN的信号传导似乎都参与了PKR的上调。GCRV对SUMOylation的抑制可能代表一种细胞抗病毒机制。
