Suppression of the phenotype of gamma(1)34.5(-) herpes simplex virus-1: Failure of activated RNA-dependent protein kinase to shut off protein synthesis is associated with a deletion in the domain of the alpha 47 gene
Suppression of the phenotype of gamma(1)34.5(-) herpes simplex virus-1: Failure of activated RNA-dependent protein kinase to shut off protein synthesis is associated with a deletion in the domain of the alpha 47 gene
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DOI：
10.1128/jvi.71.8.6049-6054.1997
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发表时间：
1997-08-01
影响因子：
5.4
通讯作者：
Roizman, B
中科院分区：
文献类型：
--
作者：
He, B;Chou, J;Roizman, B
早期研究表明，人类细胞被单纯疱疹病毒 1 (HSV-1) 感染会导致 RNA 依赖性蛋白激酶 (PKR) 激活，但 eIF-2 的 α 亚基不会磷酸化，并且蛋白质合成不受影响。在缺乏病毒 gamma(1)34.5 基因的情况下，eIF-2 α 被磷酸化，并且蛋白质合成过早关闭（J. Chou、J. J. Chen、M. Gross 和 B. Roizman, Proc. Natl. Acad. Sci. USA 92:10516-10520, 1995），最近的第二篇论文报道了第二位点抑制突变体的选择，其特征为感染γ(1)34.5(-)突变体的细胞中的近野生型蛋白质合成(I.Mohr和Y.Gluzman，EMBO J.15：4759-1766，1996)。在这里，我们报告了自发HSV-1抑制突变体Sup-1的特性，其特征是自发删除包含α47基因结构域的503bp，并与HSV-1 DNA独特短（U-s）序列侧翼的反向重复序列连接，导致α47启动子与U(s)11基因的编码结构域并置。该突变体不表现出γ(1)34.5(-)病毒的蛋白质合成特征的关闭。具体而言，SK-N-SH人神经母细胞瘤细胞中的Sup-1 (i)不表现出α 47基因的功能，其特征在于肽穿过透化细胞内质网的转运减少，与α 47基因序列的缺失一致，(ii)以与野生型亲本类似的水平积累U(s) 11蛋白，但该蛋白是在感染后较早时间产生的，正如启动子的变化所预期的那样， (iii)像亲本gamma(1)34.5(-)病毒一样激活PKR，但是(iv)不会导致蛋白质合成过早停止，因此与野生型亲本病毒相似，而不是其来源的gamma(1)34.5(-)病毒。我们得出结论，Sup-1阻断与eIF-2α被激活的PKR磷酸化相关的蛋白质合成关闭的机制不容易用二次突变来解释通过删除。
Earlier studies have shown that infection of human cells by herpes simplex virus 1 (HSV-1) results in the activation of RNA-dependent protein kinase (PKR) but that the alpha subunit of eIF-2 is not phosphorylated and that protein synthesis is unaffected. In the absence of the viral gamma(1)34.5 gene, eIF-2 alpha is phosphorylated and protein synthesis is prematurely shut off (J. Chou, J. J. Chen, M. Gross, and B. Roizman, Proc. Natl. Acad. Sci. USA 92:10516-10520, 1995), A second recent paper reported the selection of second-site suppressor mutants characterized by near-wild-type protein synthesis in cells infected with gamma(1)34.5(-) mutants (I. Mohr and Y. Gluzman, EMBO J. 15:4759-1766, 1996). Here, we report the properties of the spontaneous HSV-1 suppressor mutant Sup-1, which is characterized by spontaneous deletion of 503 bp encompassing the domain of the alpha 47 gene and junction with the inverted repeats flanking the unique short (U-s) sequence of the HSV-1 DNA resulting in the juxtaposition of the alpha 47 promoter to the coding domain of the U(s)11 gene. This mutant does not exhibit the shutoff of protein synthesis characteristic of the gamma(1)34.5(-) virus. Specifically, Sup-1 in SK-N-SH human neuroblastoma cells (i) did not exhibit the function of the alpha 47 gene characterized by a reduction in the transport of peptides across the endoplasmic reticulum of permealized cells consistent with the absence of alpha 47 gene sequences, (ii) accumulated U(s)11 protein at levels analogous to those of the wild-type parent but the protein was made at earlier times after infection, as would be expected from a change in the promoter, and (iii) activated PKR like that of the parent, gamma(1)34.5(-) virus, but (iv) did not cause premature shutoff of protein synthesis and therefore was similar to the wild-type parent virus rather than the gamma(1)34.5(-) virus from which it was derived, We conclude that the mechanism by which Sup-1 blocks the shutoff of protein synthesis associated with phosphorylation of eIF-2 alpha by the activated PKR is not readily explainable by a secondary mutation characterized by a deletion.