Takhampunya Ratree, Padmanabhan R, Ubol Sukathida
Department of Microbiology, Faculty of Science, Mahidol University, 272 Rama VI Road, Bangkok 10400, Thailand.
Department of Microbiology and Immunology, Georgetown University, School of Medicine, Washington DC, USA.
J Gen Virol. 2006 Oct;87(Pt 10):3003-3011. doi: 10.1099/vir.0.81880-0.
Recently, nitric oxide (NO) has been shown to suppress dengue virus (DENV) RNA and protein accumulation in infected cells. In this report, the potential target of the inhibitory effect of NO was studied at the molecular level. The NO donor, S-nitroso-N-acetylpenicillamine (SNAP), showed an inhibitory effect on RNA accumulation at around 8-14 h post-infection, which corresponded to the step of viral RNA synthesis in the DENV life cycle. The activity of the viral replicase isolated from SNAP-treated DENV-2-infected cells was suppressed significantly compared with that of the negative-control N-acetyl-DL-penicillamine (NAP)-treated cells. Further investigations on the molecular target of NO action showed that the activity of recombinant DENV-2 NS5 in negative-strand RNA synthesis was affected in the presence of 5 mM SNAP in in vitro RNA-dependent RNA polymerase (RdRp) assays, whereas the RNA helicase activity of DENV-2 NS3 was not inhibited up to a concentration of 15 mM SNAP. These results suggest that the inhibitory effect of NO on DENV infection is partly via inhibition of the RdRp activity, which then downregulates viral RNA synthesis.
最近，一氧化氮（NO）已被证明可抑制登革病毒（DENV）在感染细胞中的RNA和蛋白质积累。在本报告中，在分子水平上研究了NO抑制作用的潜在靶点。NO供体S-亚硝基-N-乙酰青霉胺（SNAP）在感染后约8-14小时对RNA积累表现出抑制作用，这与DENV生命周期中病毒RNA合成步骤相对应。与阴性对照N-乙酰-DL-青霉胺（NAP）处理的细胞相比，从SNAP处理的DENV-2感染细胞中分离的病毒复制酶活性受到显著抑制。对NO作用分子靶点的进一步研究表明，在体外RNA依赖性RNA聚合酶（RdRp）测定中，当存在5 mM SNAP时，重组DENV-2 NS5在负链RNA合成中的活性受到影响，而在高达15 mM SNAP的浓度下，DENV-2 NS3的RNA解旋酶活性未受到抑制。这些结果表明，NO对DENV感染的抑制作用部分是通过抑制RdRp活性，进而下调病毒RNA合成来实现的。
