Cohen J I, Seidel K
Medical Virology Section, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
J Virol. 1994 Dec;68(12):7850-8. doi: 10.1128/JVI.68.12.7850-7858.1994.
Varicella-zoster virus (VZV) open reading frame 10 (ORF10) protein in the homolog of the herpes simplex virus type 1 (HSV-1) protein VP16. VZV ORF10 transactivates the VZV IE62 gene and is a tegument protein present in the virion. HSV-1 VP16, a potent transactivator of HSV-1 immediate-early genes and tegument protein, is essential for HSV-1 replication in vitro. To determine whether VZV ORF10 is required for viral replication in vitro, we constructed two VZV mutants which were unable to express ORF10. One mutant had a stop codon after the 61st codon of the ORF10 gene, and the other mutant was deleted for all but the last five codons of the gene. Both VZV mutants grew in cell culture to titers similar to that of the parental virus. To determine whether HSV-1 VP16 alters the growth of VZV, we constructed a VZV mutant in which VP16 was inserted in place of ORF10. Using immune electron microscopy, we found that HSV-1 VP16 was present in the tegument of the recombinant VZV virions. The VZV VP16 substitution mutant produced smaller plaques and grew to a lower titer than parental virus. Thus, VZV ORF10 is not required for growth of the virus in vitro, and substitution of HSV-1 VP16 for VZV ORF10 impairs the growth of VZV.
水痘带状疱疹病毒（VZV）开放阅读框10（ORF10）蛋白与单纯疱疹病毒1型（HSV-1）蛋白VP16同源。VZV ORF10可反式激活VZV IE62基因，并且是存在于病毒体中的一种被膜蛋白。HSV-1 VP16是HSV-1立即早期基因的有效反式激活因子和被膜蛋白，对HSV-1在体外复制至关重要。为了确定VZV ORF10在体外病毒复制中是否必需，我们构建了两个无法表达ORF10的VZV突变体。一个突变体在ORF10基因的第61个密码子之后有一个终止密码子，另一个突变体除该基因的最后五个密码子外全部缺失。这两个VZV突变体在细胞培养中的生长滴度与亲本病毒相似。为了确定HSV-1 VP16是否会改变VZV的生长，我们构建了一个用VP16取代ORF10的VZV突变体。通过免疫电子显微镜，我们发现HSV-1 VP16存在于重组VZV病毒体的被膜中。VZV VP16替代突变体产生的蚀斑较小，生长滴度低于亲本病毒。因此，VZV ORF10在体外病毒生长中不是必需的，用HSV-1 VP16替代VZV ORF10会损害VZV的生长。
