Center for Immunotherapy, Vaccines, and Virotherapy, Biodesign Institute, Arizona State University, Tempe, AZ 85287.
School of Life Sciences, Arizona State University, Tempe, AZ 85287.
Proc Natl Acad Sci U S A. 2017 Oct 24;114(43):11506-11511. doi: 10.1073/pnas.1700999114. Epub 2017 Oct 9.
Vaccinia virus (VACV) encodes an innate immune evasion protein, E3, which contains an N-terminal Z-nucleic acid binding (Zα) domain that is critical for pathogenicity in mice. Here we demonstrate that the N terminus of E3 is necessary to inhibit an IFN-primed virus-induced necroptosis. VACV deleted of the Zα domain of E3 (VACV-E3LΔ83N) induced rapid RIPK3-dependent cell death in IFN-treated L929 cells. Cell death was inhibited by the RIPK3 inhibitor, GSK872, and infection with this mutant virus led to phosphorylation and aggregation of MLKL, the executioner of necroptosis. In 293T cells, induction of necroptosis depended on expression of RIPK3 as well as the host-encoded Zα domain-containing DNA sensor, DAI. VACV-E3LΔ83N is attenuated in vivo, and pathogenicity was restored in either RIPK3- or DAI-deficient mice. These data demonstrate that the N terminus of the VACV E3 protein prevents DAI-mediated induction of necroptosis.
痘苗病毒（VACV）编码一种先天免疫逃避蛋白 E3，它包含一个 N 端 Z-核酸结合（Zα）结构域，对于在小鼠中的致病性至关重要。在这里，我们证明 E3 的 N 端对于抑制 IFN 引发的病毒诱导的坏死性凋亡是必需的。缺失 E3 的 Zα 结构域的 VACV（VACV-E3LΔ83N）在 IFN 处理的 L929 细胞中迅速诱导 RIPK3 依赖性细胞死亡。RIPK3 抑制剂 GSK872 抑制细胞死亡，并且该突变病毒的感染导致坏死性凋亡的执行者 MLKL 的磷酸化和聚集。在 293T 细胞中，坏死性凋亡的诱导依赖于 RIPK3 的表达以及宿主编码的含有 Zα 结构域的 DNA 传感器 DAI。VACV-E3LΔ83N 在体内减毒，并且在 RIPK3 或 DAI 缺陷型小鼠中恢复了致病性。这些数据表明，VACV E3 蛋白的 N 端防止 DAI 介导的坏死性凋亡的诱导。
