Identification of the rabies virus alpha/beta interferon antagonist:: Phosphoprotein P interferes with phosphorylation of interferon regulatory factor 3
Identification of the rabies virus alpha/beta interferon antagonist:: Phosphoprotein P interferes with phosphorylation of interferon regulatory factor 3
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DOI：
10.1128/jvi.79.12.7673-7681.2005
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发表时间：
2005-06-01
影响因子：
5.4
通讯作者：
Conzelmann, KK
中科院分区：
文献类型：
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作者：
Brzózka, K;Finke, S;Conzelmann, KK
弹状病毒科的狂犬病病毒 (RV) 在 α/β 干扰素 (IFN) 感受态细胞中生长，表明存在阻止 IFN 基因表达的病毒机制。我们在此将病毒磷蛋白 P 确定为负责的 IFN 拮抗剂。 P 的关键参与首先是通过如下观察发现的：与野生型 (wt) RV 或野生型 (wt) RV 或RV 复制子缺乏基质蛋白和糖蛋白基因。 SAD eGFP-P 诱导 IFN-β 基因的转录以及 IFN 响应性 MxA 和 STAT-1 基因的表达。同样，通过将 P 基因移至启动子远端基因位置 (SAD APLP) 产生的表达低水平 P 的 RV 失去了阻止 IFN 诱导的能力。对缺乏截短 P 蛋白 P2、P3 或 P4 表达的 RV 突变体的分析进一步表明，全长 P 能够抑制 IFN-β 基因表达，这些蛋白由 wt RV P 开放阅读框的内部 AUG 密码子表达。与wt RV相比，IFN诱导的SAD APLP引起S386磷酸化、二聚化和IFN调节因子3（IRF-3）的转录活性。由转染质粒表达的 TANK 结合激酶 1 对 IRF-3 的磷酸化在 wt RV 感染的细胞中或通过 P 编码质粒的共转染被消除。因此，RV P 通过上游激酶靶向激活 IRF-3 来防止病毒感染细胞中的关键 IFN 反应是必要且充分的。
Rabies virus (RV) of the Rhabdoviridae family grows in alpha/beta interferon (IFN)-competent cells, suggesting the existence of viral mechanisms preventing IFN gene expression. We here identify the viral phosphoprotein P as the responsible IFN antagonist. The critical involvement of P was first suggested by the observation that an RV expressing an enhanced green fluorescent protein (eGFP)-P fusion protein (SAD eGFP-P) (S. Finke, K. Brzozka, and K. K. Conzelmann, J. Virol. 78:12333-12343, 2004) was eliminated in IFN-competent HEp-2 cell cultures, in contrast to wild-type (wt) RV or an RV replicon lacking the genes for matrix protein and glycoprotein. SAD eGFP-P induced transcription of the IFN-beta gene and expression of the IFN-responsive MxA and STAT-1 genes. Similarly, an RV expressing low levels of P, which was generated by moving the P gene to a promoter-distal gene position (SAD APLP), lost the ability to prevent IFN induction. The analysis of RV mutants lacking expression of truncated P proteins P2, P3, or P4, which are expressed from internal AUG codons of the wt RV P open reading frame, further showed that full-length P is competent in suppressing IFN-beta gene expression. In contrast to wt RV, the IFN-inducing SAD APLP caused S386 phosphorylation, dimerization, and transcriptional activity of IFN regulatory factor 3 (IRF-3). Phosphorylation of IRF-3 by TANK-binding kinase-1 expressed from transfected plasmids was abolished in wt RV-infected cells or by cotransfection of P-encoding plasmids. Thus, RV P is necessary and sufficient to prevent a critical IFN response in virus-infected cells by targeting activation of IRF-3 by an upstream kinase.