Umareddy Indira, Chao Alex, Sampath Aruna, Gu Feng, Vasudevan Subhash G
Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670.
J Gen Virol. 2006 Sep;87(Pt 9):2605-2614. doi: 10.1099/vir.0.81844-0.
Dengue virus, a member of the family Flaviviridae of positive-strand RNA viruses, has seven non-structural proteins: NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5. Except for enzymic activities contained within NS3 and NS5, the roles of the other proteins in virus replication and pathogenesis are not well defined. In this study, a physical interaction between NS4B and the helicase domain of NS3 was identified by using a yeast two-hybrid assay. This interaction was further confirmed by biochemical pull-down and immunoprecipitation assays, both with purified proteins and with dengue virus-infected cell lysates. NS4B co-localized with NS3 in the perinuclear region of infected human cells. Furthermore, NS4B dissociated NS3 from single-stranded RNA and consequently enhanced the helicase activity of NS3 in an in vitro unwinding assay. These results suggest that NS4B modulates dengue virus replication via its interaction with NS3.
登革病毒是正链RNA病毒黄病毒科的成员，有七种非结构蛋白：NS1、NS2A、NS2B、NS3、NS4A、NS4B和NS5。除了NS3和NS5所包含的酶活性外，其他蛋白在病毒复制和发病机制中的作用尚未明确。在本研究中，通过酵母双杂交试验鉴定出NS4B与NS3解旋酶结构域之间存在物理相互作用。这种相互作用通过生化下拉试验和免疫沉淀试验进一步得到证实，所用材料既有纯化蛋白，也有登革病毒感染的细胞裂解物。NS4B与NS3在受感染人类细胞的核周区域共定位。此外，在体外解旋试验中，NS4B使NS3与单链RNA解离，从而增强了NS3的解旋酶活性。这些结果表明，NS4B通过与NS3相互作用来调节登革病毒的复制。
