Zhou Jing, Wang Shi-Qi, Wei Jian-Chao, Zhang Xiao-Min, Gao Zhi-Can, Liu Ke, Ma Zhi-Yong, Chen Pu-Yan, Zhou Bin
Key Laboratory of Animal Diseases Diagnosis and Immunology, Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China.
Viruses. 2017 Jan 10;9(1):5. doi: 10.3390/v9010005.
Mx proteins are interferon (IFN)-induced dynamin-like GTPases that are present in all vertebrates and inhibit the replication of myriad viruses. However, the role Mx proteins play in IFN-mediated suppression of Japanese encephalitis virus (JEV) infection is unknown. In this study, we set out to investigate the effects of Mx1 and Mx2 expression on the interferon-α (IFNα) restriction of JEV replication. To evaluate whether the inhibitory activity of IFNα on JEV is dependent on Mx1 or Mx2, we knocked down Mx1 or Mx2 with siRNA in IFNα-treated PK-15 cells and BHK-21 cells, then challenged them with JEV; the production of progeny virus was assessed by plaque assay, RT-qPCR, and Western blotting. Our results demonstrated that depletion of Mx1 or Mx2 did not affect JEV restriction imposed by IFNα, although these two proteins were knocked down 66% and 79%, respectively. Accordingly, expression of exogenous Mx1 or Mx2 did not change the inhibitory activity of IFNα to JEV. In addition, even though virus-induced membranes were damaged by Brefeldin A (BFA), overexpressing porcine Mx1 or Mx2 did not inhibit JEV proliferation. We found that BFA inhibited JEV replication, not maturation, suggesting that BFA could be developed into a novel antiviral reagent. Collectively, our findings demonstrate that IFNα inhibits JEV infection by Mx-independent pathways.
Mx蛋白是干扰素（IFN）诱导的动力蛋白样GTP酶，存在于所有脊椎动物中，可抑制多种病毒的复制。然而，Mx蛋白在IFN介导的抑制日本脑炎病毒（JEV）感染中所起的作用尚不清楚。在本研究中，我们着手研究Mx1和Mx2表达对JEV复制的干扰素-α（IFNα）限制作用的影响。为了评估IFNα对JEV的抑制活性是否依赖于Mx1或Mx2，我们在经IFNα处理的PK-15细胞和BHK-21细胞中用小干扰RNA（siRNA）敲低Mx1或Mx2，然后用JEV攻击它们；通过蚀斑测定、逆转录定量聚合酶链反应（RT-qPCR）和蛋白质免疫印迹法评估子代病毒的产生。我们的结果表明，尽管Mx1和Mx2分别被敲低了66%和79%，但敲低Mx1或Mx2并不影响IFNα对JEV的限制作用。因此，外源性Mx1或Mx2的表达并没有改变IFNα对JEV的抑制活性。此外，即使布雷菲德菌素A（BFA）破坏了病毒诱导的膜，过表达猪Mx1或Mx2也不会抑制JEV的增殖。我们发现BFA抑制JEV的复制，而不是成熟，这表明BFA可被开发成一种新型抗病毒试剂。总的来说，我们的研究结果表明，IFNα通过不依赖Mx的途径抑制JEV感染。
