Reid St Patrick, Cárdenas Washington B, Basler Christopher F
Department of Microbiology, Box 1124, Mount Sinai School of Medicine, 1 Gustave L. Levy Place, New York, NY 10029, USA.
Virology. 2005 Oct 25;341(2):179-89. doi: 10.1016/j.virol.2005.06.044. Epub 2005 Aug 10.
We have identified a putative coiled-coil motif within the amino-terminal half of the ebolavirus VP35 protein. Cross-linking studies demonstrated the ability of VP35 to form trimers, consistent with the presence of a functional coiled-coil motif. VP35 mutants lacking the coiled-coil motif or possessing a mutation designed to disrupt coiled-coil function were defective in oligomerization, as deduced by co-immunoprecipitation studies. VP35 inhibits signaling that activates interferon regulatory factor 3 (IRF-3) and inhibits (IFN)-alpha/beta production. Experiments comparing the ability of VP35 mutants to block IFN responses demonstrated that the VP35 amino-terminus, which retains the putative coiled-coil motif, was unable to inhibit IFN responses, whereas the VP35 carboxy-terminus weakly inhibited the activation of IFN responses. IFN-antagonist function was restored when a heterologous trimerization motif was fused to the carboxy-terminal half of VP35, suggesting that an oligomerization function at the amino-terminus facilitates an "IFN-antagonist" function exerted by the carboxy-terminal half of VP35.
我们在埃博拉病毒VP35蛋白氨基末端的前半部分鉴定出一个假定的卷曲螺旋基序。交联研究证明VP35能够形成三聚体，这与存在功能性卷曲螺旋基序相一致。通过免疫共沉淀研究推断，缺乏卷曲螺旋基序或具有旨在破坏卷曲螺旋功能的突变的VP35突变体在寡聚化方面存在缺陷。VP35抑制激活干扰素调节因子3（IRF-3）的信号传导并抑制α/β干扰素（IFN）的产生。比较VP35突变体阻断IFN反应能力的实验表明，保留假定卷曲螺旋基序的VP35氨基末端无法抑制IFN反应，而VP35羧基末端则微弱地抑制IFN反应的激活。当一个异源三聚化基序与VP35的羧基末端后半部分融合时，IFN拮抗剂功能得以恢复，这表明氨基末端的寡聚化功能促进了VP35羧基末端后半部分发挥的“IFN拮抗剂”功能。
