Moriuchi H, Moriuchi M, Cohen J I
Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892, USA.
J Virol. 1995 Aug;69(8):4693-701. doi: 10.1128/JVI.69.8.4693-4701.1995.
Varicella-zoster virus (VZV) open reading frame 10 (ORF10) protein, the homolog of herpes simplex virus type 1 (HSV-1) VP16, is a virion-associated transactivator of the VZV immediate-early (IE) gene 62 (IE62) promoter. VP16 forms a complex with cellular factors (Oct1 and host cell factor [HCF]) and TAATGARAT elements (found in all HSV-1 IE promoter/enhancer sequences) to mediate stimulation of IE transcription. The VZV IE62 promoter also contains three TAATGARAT-like elements. Mutagenesis studies of the VZV IE62 promoter indicated that TAATGARAT-like elements contribute to transactivation of the VZV IE62 promoter by ORF10 protein. Other cis-acting elements such as GA-rich and cyclic AMP-responsive elements were also needed for full transactivation by ORF10 protein. In mobility shift assays, ORF10 protein formed a complex with either of two TAATGARAT-like elements that lack an overlapping octamer-binding motif (octa-/TAATGARAT) but not with a TAATGARAT element with an overlapping octamer-binding motif (octa+/TAATGARAT). In contrast, VP16 formed a high-affinity ternary complex with an octa+/TAATGARAT element and a low-affinity complex with octa-/TAATGARAT elements. Addition of antibodies to ORF10 protein, Oct1, or HCF disrupted the complexes, demonstrating that ORF10 protein interacts with Oct1 and HCF. These results suggest that transactivation of the VZV IE62 gene by ORF10 protein and HSV IE genes by VP16 require similar cellular proteins but distinct cis-acting elements.
水痘带状疱疹病毒（VZV）开放阅读框10（ORF10）蛋白是1型单纯疱疹病毒（HSV-1）VP16的同源物，是一种与病毒粒子相关的VZV立即早期（IE）基因62（IE62）启动子的反式激活因子。VP16与细胞因子（Oct1和宿主细胞因子[HCF]）以及TAATGARAT元件（存在于所有HSV-1 IE启动子/增强子序列中）形成复合物，以介导IE转录的刺激。VZV IE62启动子也包含三个TAATGARAT样元件。对VZV IE62启动子的诱变研究表明，TAATGARAT样元件有助于ORF10蛋白对VZV IE62启动子的反式激活。ORF10蛋白完全反式激活还需要其他顺式作用元件，如富含GA的元件和环磷酸腺苷反应元件。在凝胶迁移试验中，ORF10蛋白与两个缺乏重叠八聚体结合基序（八聚体/TAATGARAT）的TAATGARAT样元件之一形成复合物，但不与具有重叠八聚体结合基序（八聚体+/TAATGARAT）的TAATGARAT元件形成复合物。相比之下，VP16与八聚体+/TAATGARAT元件形成高亲和力三元复合物，与八聚体/TAATGARAT元件形成低亲和力复合物。添加针对ORF10蛋白、Oct1或HCF的抗体可破坏复合物，表明ORF10蛋白与Oct1和HCF相互作用。这些结果表明，ORF10蛋白对VZV IE62基因的反式激活以及VP16对HSV IE基因的反式激活需要相似的细胞蛋白，但顺式作用元件不同。
