Selective ablation of virion host shutoff protein RNase activity attenuates herpes simplex virus 2 in mice
Selective ablation of virion host shutoff protein RNase activity attenuates herpes simplex virus 2 in mice
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DOI：
10.1128/jvi.02409-07
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发表时间：
2008-04-01
影响因子：
5.4
通讯作者：
Morrison, Lynda A.
中科院分区：
文献类型：
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作者：
Korom, Maria;Wylie, Kristine M.;Morrison, Lynda A.
单纯疱疹病毒（HSV）的病毒体宿主关闭（vhs）蛋白具有核糖核酸内切酶活性，并通过mRNA降解快速减少感染细胞中的蛋白质合成。单纯疱疹病毒1（HSV-1）和HSV-2 vhs突变体在体内高度减毒，但在不存在I型干扰素（IFN）应答的情况下，HSV-2 vhs突变体的复制和毒力在很大程度上恢复。VHS在发病机制中的作用和I型IFN应答的阻碍已经经典地用完全缺乏VHS或表达截短的VHS蛋白的病毒进行了研究。为了确定RNA酶活性是否是vhs介导的I型IFN抗性和毒力的主要机制，我们构建了HSV-2点突变体，其合成缺乏RNA酶活性的全长vhs蛋白（RNA酶（-）病毒）。野生型和突变型HSV-2 vhs蛋白与VP 16和VP 22共免疫沉淀。携带点突变的VHS蛋白质与野生型VHS蛋白质一样有效地包装到病毒粒子中。与编码截短型vhs的突变体一样，RNase（-）病毒显示出与野生型病毒相比受到限制的IFN依赖性复制。RNase（-）病毒在阴道内感染的野生型小鼠中高度减毒，粘膜复制减少，疾病严重程度降低，并扩散到神经系统，与vhs截短突变体相当。令人惊讶的是，在α/β干扰素（IFN-α/β）受体敲除小鼠中，在阴道拭子和中枢神经系统样品中，就疾病严重程度和病毒滴度而言，vhs RNA酶突变体比vhs截短突变体更弱，这表明非酶活性vhs蛋白干扰有效的病毒复制。我们的研究结果表明，在HSV-2感染过程中，VHS酶活性在VHS介导的I型IFN抗性中起着复杂的作用。
The virion host shutoff (vhs) protein of herpes simplex virus (HSV) has endoribonuclease activity and rapidly reduces protein synthesis in infected cells through mRNA degradation. Herpes simplex virus 1 (HSV-1) and HSV-2 vhs mutants are highly attenuated in vivo, but replication and virulence are largely restored to HSV-2 vhs mutants in the absence of a type I interferon (IFN) response. The role of vhs in pathogenesis and the hindrance of the type I IFN response have classically been examined with viruses that completely lack vhs or express a truncated vhs protein. To determine whether RNase activity is the principal mechanism of vhs-mediated type I IFN resistance and virulence, we constructed a HSV-2 point mutant that synthesizes full-length vhs protein lacking RNase activity (RNase(-) virus). Wild-type and mutant HSV-2 vhs proteins coimmunoprecipitated with VP16 and VP22. vhs protein bearing the point mutation was packaged into the virion as efficiently as the wild-type vhs protein. Like a mutant encoding truncated vhs, the RNase(-) virus showed IFN-dependent replication that was restricted compared with that of the wild-type virus. The RNase(-) virus was highly attenuated in wild-type mice infected intravaginally, with reduced mucosal replication, disease severity, and spread to the nervous system comparable to those of the vhs truncation mutant. Surprisingly, in alpha/beta interferon (IFN-alpha/beta) receptor knockout mice, the vhs RNase mutant was more attenuated than the vhs truncation mutant in terms of disease severity and virus titer in vaginal swabs and central nervous system samples, suggesting that non-enzymatically active vhs protein interferes with efficient virus replication. Our results indicate that vhs enzymatic activity plays a complex role in vhs-mediated type I IFN resistance during HSV-2 infection.