Deletion in Open Reading Frame 49 of Varicella-Zoster Virus Reduces Virus Growth in Human Malignant Melanoma Cells but Not in Human Embryonic Fibroblasts
Deletion in Open Reading Frame 49 of Varicella-Zoster Virus Reduces Virus Growth in Human Malignant Melanoma Cells but Not in Human Embryonic Fibroblasts
复制标题
水痘带状疱疹病毒开放阅读框 49 的缺失可减少人恶性黑色素瘤细胞中的病毒生长，但不会减少人胚胎成纤维细胞中的病毒生长
作者：
Tomohiko Sadaoka;Hironori Yoshii;T. Imazawa;K. Yamanishi;Y. Mori
水痘-带状疱疹病毒（VZV）的ORF 49基因产物（ORF 49 p）可能是一种肉豆蔻化的被膜蛋白，其同源物在疱疹病毒亚科中是保守的。单纯疱疹病毒1型和伪狂犬病病毒的UL 11基因和人巨细胞病毒的UL 99基因是ORF 49的同源物，并已通过使用突变病毒得到很好的表征;然而，很少有关于VZV ORF 49基因的研究报道。在这里，我们报告VZV ORF 49 p的表达，亚细胞定位，并在体外对病毒传播的影响。ORF 49 p在感染后期表达，位于胞质的胞核区域，主要与trans-Golgi网络相关蛋白共定位。ORF 49 p被整合到病毒体中，并在VZV感染的细胞和病毒体中显示出13 kDa的分子量。为了阐明ORF 49基因的作用，我们构建了一种缺乏功能性ORF 49的突变病毒。在感染野生型或突变型病毒的人胚胎成纤维细胞MRC-5细胞中未观察到空斑大小或细胞间扩散的差异。然而，突变病毒在人恶性黑色素瘤细胞系MeWo细胞中表现出细胞间感染减少。因此，VZV ORF 49 p对MeWo细胞中的病毒生长很重要，但对MRC-5细胞中的病毒生长不重要。VZV在MeWo和MRC-5细胞中的病毒生长可能使用不同的机制。如果是这样的话，了解ORF 49 p的作用应该有助于阐明VZV如何在不同的细胞类型中完成细胞-细胞感染。
ABSTRACT The ORF49 gene product (ORF49p) of the varicella-zoster virus (VZV) is likely a myristylated tegument protein, and its homologs are conserved across the herpesvirus subfamilies. The UL11 gene of herpes simplex virus type 1 and of pseudorabies virus and the UL99 gene of human cytomegalovirus are the homologs of ORF49 and have been well characterized by using mutant viruses; however, little research on the VZV ORF49 gene has been reported. Here we report on VZV ORF49p expression, subcellular localization, and effect on viral spread in vitro. ORF49p was expressed during the late phase of infection and located in the juxtanuclear region of the cytoplasm, where it colocalized mainly with the trans-Golgi network-associated protein. ORF49p was incorporated into virions and showed a molecular mass of 13 kDa in VZV-infected cells and virions. To elucidate the role of the ORF49 gene, we constructed a mutant virus that lacked a functional ORF49. No differences in plaque size or cell-cell spread were observed in human embryonic fibroblast cells, MRC-5 cells, infected with the wild-type or the mutant virus. However, the mutant virus showed diminished cell-cell infection in a human malignant melanoma cell line, MeWo cells. Therefore, VZV ORF49p is important for virus growth in MeWo cells, but not in MRC-5 cells. VZV may use different mechanisms for virus growth in MeWo and MRC-5 cells. If so, understanding the role of ORF49p should help elucidate how VZV accomplishes cell-cell infections in different cell types.