Jayachandra S, Baghian A, Kousoulas K G
Department of Veterinary Microbiology and Parasitology, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803, USA.
J Virol. 1997 Jul;71(7):5012-24. doi: 10.1128/JVI.71.7.5012-5024.1997.
We characterized the glycoprotein K (gK)-null herpes simplex virus type 1 [HSV-1] (KOS) delta gK and compared it to the gK-null virus HSV-1 F-gKbeta (L. Hutchinson et al., J. Virol. 69:5401-5413, 1995). delta gK and F-gKbeta mutant viruses produced small plaques on Vero cell monolayers at 48 h postinfection. F-gKbeta caused extensive fusion of 143TK cells that was sensitive to melittin, a specific inhibitor of gK-induced cell fusion, while delta gK virus did not fuse 143TK cells. A recombinant plasmid containing the truncated gK gene specified by F-gKbeta failed to rescue the ICP27-null virus KOS (d27-1), while a plasmid with the delta gK deletion rescued the d27-1 virus efficiently. delta gK virus yield was approximately 100,000-fold lower in stationary cells than in actively replicating Vero cells. The plaquing efficiencies of delta gK and F-gKbeta virus stocks on VK302 cells were similar, while the plaquing efficiency of F-gKbeta virus stocks on Vero cells was reduced nearly 10,000-fold in comparison to that of delta gK virus. Mutant delta gK and F-gKbeta infectious virions accumulated within Vero and HEp-2 cells but failed to translocate to extracellular spaces. delta gK capsids accumulated in the nuclei of Vero but not HEp-2 cells. Enveloped delta gK virions were visualized in the cytoplasms of both Vero and HEp-2 cells, and viral capsids were found in the cytoplasm of HEp-2 cells within vesicles. Glycoproteins B, C, D, and H were expressed on the surface of delta gK-infected Vero cells in amounts similar to those for KOS-infected Vero cells. These results indicate that gK is involved in nucleocapsid envelopment, and more importantly in the translocation of infectious virions from the cytoplasm to the extracellular spaces, and that actively replicating cells can partially compensate for the envelopment but not for the cellular egress deficiency of the delta gK virus. Comparison of delta gK and F-gKbeta viruses suggests that the inefficient viral replication and plaquing efficiency of F-gKbeta virus in Vero cells and its syncytial phenotype in 143TK- cells are most likely due to expression of a truncated gK.
我们对糖蛋白K（gK）缺失的单纯疱疹病毒1型[HSV - 1]（KOS）ΔgK进行了特性分析，并将其与gK缺失病毒HSV - 1 F - gKβ（L. Hutchinson等人，《病毒学杂志》69:5401 - 5413，1995年）进行了比较。ΔgK和F - gKβ突变病毒在感染后48小时在Vero细胞单层上形成小斑块。F - gKβ导致143TK细胞广泛融合，这种融合对蜂毒肽敏感，蜂毒肽是gK诱导的细胞融合的特异性抑制剂，而ΔgK病毒不会使143TK细胞融合。含有由F - gKβ指定的截短gK基因的重组质粒未能拯救ICP27缺失病毒KOS（d27 - 1），而带有ΔgK缺失的质粒有效地拯救了d27 - 1病毒。在静止细胞中，ΔgK病毒产量比在活跃复制的Vero细胞中低约100,000倍。ΔgK和F - gKβ病毒株在VK302细胞上的噬斑形成效率相似，而与ΔgK病毒相比，F - gKβ病毒株在Vero细胞上的噬斑形成效率降低了近10,000倍。突变的ΔgK和F - gKβ感染性病毒粒子在Vero和HEp - 2细胞内积累，但未能转运到细胞外空间。ΔgK衣壳在Vero细胞的细胞核中积累，但不在HEp - 2细胞中积累。在Vero和HEp - 2细胞的细胞质中都能看到被包膜的ΔgK病毒粒子，并且在HEp - 2细胞细胞质内的囊泡中发现了病毒衣壳。糖蛋白B、C、D和H在被ΔgK感染的Vero细胞表面的表达量与被KOS感染的Vero细胞相似。这些结果表明，gK参与核衣壳包膜过程，更重要的是参与感染性病毒粒子从细胞质向细胞外空间的转运，并且活跃复制的细胞可以部分补偿ΔgK病毒的包膜缺陷，但不能补偿其细胞外排出缺陷。对ΔgK和F - gKβ病毒的比较表明，F - gKβ病毒在Vero细胞中低效的病毒复制和噬斑形成效率以及其在143TK细胞中的合胞体表型很可能是由于截短gK的表达。
