Desai P, DeLuca N A, Person S
Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, Maryland 21205, USA.
Virology. 1998 Jul 20;247(1):115-24. doi: 10.1006/viro.1998.9230.
VP26 is the smallest capsid protein of herpes simplex virus type 1 and is encoded by the UL35 open reading frame. It resides on the outer capsid surface, interacting with VP5 in a one to one stoichiometry in the hexons that comprise capsids. A null mutation in the gene encoding VP26 was generated and transferred into the KOS genome. Recombinant viruses were isolated on Vero cells, which indicated that the absence of VP26 was not required for growth of the virus in cell culture. This was confirmed by the characterization of the VP26 null mutant, designated K delta 26Z. The yield of virus from K delta 26Z-infected Vero cells was decreased only twofold relative to wild-type-infected cells, as judged by the burst size. All three types of capsids (A, B, and C) were observed after sedimentation analysis of K delta 26Z-infected cell extracts. These capsids were similar in composition to wild-type capsids except for the absence of VP26. The mouse ocular model was used to determine if VP26 played a major role in vivo. The yield of the mutant virus relative to wild-type virus was decreased twofold in the eye; however, the mutant virus yields were decreased 30- to 100-fold in the trigeminal ganglia. Reactivation of the mutant virus as determined by cocultivation assays was also reduced. To determine the effect of VP26 on capsid translocation, the VP26 null mutation was transferred into a virus specifiying a thymidine kinase mutation that by itself is transported to the trigeminal ganglia but whose DNA is not replicated in the ganglia. Using quantitative PCR assays the number of viral genomes detected in the ganglia was similar in the presence or the absence of VP26. Therefore, VP26 does not appear to aid in the translocation of the virus capsid from the mouse eye to the trigeminal ganglia but is important for infectious virus production in the ganglia.
VP26是单纯疱疹病毒1型最小的衣壳蛋白，由UL35开放阅读框编码。它位于病毒外衣壳表面，在构成衣壳的六邻体中以1:1的化学计量比与VP5相互作用。编码VP26的基因产生了无效突变，并被转入KOS基因组。在Vero细胞上分离出重组病毒，这表明在细胞培养中病毒生长不需要VP26的存在。这一点通过对命名为Kδ26Z的VP26无效突变体的特性分析得到了证实。根据爆发量判断，来自感染Kδ26Z的Vero细胞的病毒产量相对于感染野生型的细胞仅降低了两倍。对感染Kδ26Z的细胞提取物进行沉降分析后，观察到了所有三种类型的衣壳（A、B和C）。除了没有VP26外，这些衣壳的组成与野生型衣壳相似。使用小鼠眼部模型来确定VP26在体内是否起主要作用。相对于野生型病毒，突变病毒在眼中的产量降低了两倍；然而，突变病毒在三叉神经节中的产量降低了30至100倍。通过共培养试验确定的突变病毒的重新激活也减少了。为了确定VP26对衣壳转运的影响，将VP26无效突变转入一种指定胸苷激酶突变的病毒中，该病毒自身可转运至三叉神经节，但其DNA不在神经节中复制。使用定量PCR分析，在有或没有VP26的情况下，在神经节中检测到的病毒基因组数量相似。因此，VP26似乎无助于病毒衣壳从小鼠眼睛转运至三叉神经节，但对神经节中感染性病毒的产生很重要。
