Stewart J P, Janjua N J, Sunil-Chandra N P, Nash A A, Arrand J R
CRC Department of Molecular Biology, Paterson Institute for Cancer Research, Christie Hospital, Manchester, United Kingdom.
J Virol. 1994 Oct;68(10):6496-504. doi: 10.1128/JVI.68.10.6496-6504.1994.
Murine gammaherpesvirus 68 (MHV-68) is a natural pathogen of murid rodents and displays similar pathobiological characteristics to those of the human gammaherpesvirus Epstein-Barr virus (EBV). However, in contrast to EBV, MHV-68 will replicate in epithelial cells in vitro. It has therefore been proposed that MHV-68 may be of use as a model for the study of gammaherpesviruses, EBV in particular, both in vitro and in vivo. The EBV homolog of herpes simplex virus glycoprotein B (gB), termed gp110, is somewhat unusual compared with those of many other herpesviruses. We therefore decided to characterize the homolog of gB encoded by MHV-68 (termed MHV gB) to observe the properties of a gammaherpesvirus gB produced in epithelial cells and also to test the relatedness of MHV-68 and EBV. The MHV gB-coding sequence was determined from cloned DNA. The predicted amino acid sequence shared closest homology with gammaherpesvirus gB homologs. Biochemical analysis showed that MHV gB was a glycoprotein with a molecular weight of 105,000. However, the glycans were of the N-linked, high-mannose type, indicating retention in the endoplasmic reticulum. In line with this, MHV gB was localized to the cytoplasm and nuclear margins of infected cells but was not detected on the cell surface or in virions. Additionally, anti-MHV gB antisera were nonneutralizing. Thus, the MHV gB was unlike many other herpesvirus gBs but was extremely similar to the EBV gB. This highlights the close relationship between MHV-68 and EBV and underlines the potential of MHV-68 as a model for EBV in epithelial cells both in vitro and in vivo.
鼠γ-疱疹病毒68（MHV-68）是鼠科啮齿动物的天然病原体，具有与人类γ-疱疹病毒爱泼斯坦-巴尔病毒（EBV）相似的病理生物学特征。然而，与EBV不同的是，MHV-68能在体外上皮细胞中复制。因此，有人提出MHV-68可作为研究γ-疱疹病毒，尤其是EBV在体外和体内的模型。单纯疱疹病毒糖蛋白B（gB）的EBV同源物，称为gp110，与许多其他疱疹病毒的同源物相比有些不同寻常。因此，我们决定对MHV-68编码的gB同源物（称为MHV gB）进行表征，以观察在上皮细胞中产生的γ-疱疹病毒gB的特性，并测试MHV-68与EBV的相关性。从克隆的DNA中确定了MHV gB的编码序列。预测的氨基酸序列与γ-疱疹病毒gB同源物具有最密切的同源性。生化分析表明，MHV gB是一种分子量为105,000的糖蛋白。然而，聚糖是N-连接的高甘露糖型，表明保留在内质网中。与此一致的是，MHV gB定位于受感染细胞的细胞质和核边缘，但在细胞表面或病毒粒子中未检测到。此外，抗MHV gB抗血清无中和作用。因此，MHV gB与许多其他疱疹病毒gB不同，但与EBV gB极为相似。这突出了MHV-68与EBV之间的密切关系，并强调了MHV-68作为EBV在体外和体内上皮细胞模型的潜力。
