Lium E K, Panagiotidis C A, Wen X, Silverstein S J
Department of Microbiology and College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
J Virol. 1998 Oct;72(10):7785-95. doi: 10.1128/JVI.72.10.7785-7795.1998.
The transcriptional program of herpes simplex virus is regulated by the concerted action of three immediate-early (alpha) proteins, ICP4, ICP27, and ICP0. The experiments described in this study examine the role of the acidic amino terminus (amino acids 1 to 103) of ICP0 in gene activation. When tethered to a DNA binding domain, this sequence activates transcription in the yeast Saccharomyces cerevisiae. Deletion of these amino acids affects the ability of ICP0 to activate alpha-gene promoter reporters in transient expression assays, while it has little or no effect on a beta- and a gamma-gene reporter in the same assay. Viruses that express the deleted form of ICP0 (ICP0-NX) have a small-plaque phenotype on both Vero cells and the complementing cell line L7. Transient expression and immunofluorescence analyses demonstrate that ICP0-NX is a dominant negative form of ICP0. Immunoprecipitation of ICP0 from cells coinfected with viruses expressing ICP0-NX and ICP0 revealed that ICP0 oligomerizes in infected cells. These data, in conjunction with the finding that ICP0-N/X is dominant negative, provide both biochemical and genetic evidence that ICP0 functions as a multimer in infected cells.
单纯疱疹病毒的转录程序受三种立即早期（α）蛋白ICP4、ICP27和ICP0的协同作用调控。本研究中描述的实验考察了ICP0酸性氨基末端（氨基酸1至103）在基因激活中的作用。当与DNA结合结构域相连时，该序列可在酿酒酵母中激活转录。在瞬时表达试验中，缺失这些氨基酸会影响ICP0激活α基因启动子报告基因的能力，而在同一试验中对β基因和γ基因报告基因几乎没有影响。表达缺失形式ICP0（ICP0-NX）的病毒在Vero细胞和互补细胞系L7上均具有小斑块表型。瞬时表达和免疫荧光分析表明，ICP0-NX是ICP0的显性负性形式。从共感染表达ICP0-NX和ICP0的病毒的细胞中免疫沉淀ICP0，结果显示ICP0在感染细胞中发生寡聚化。这些数据，结合ICP0-N/X是显性负性的这一发现，提供了生化和遗传学证据，表明ICP0在感染细胞中作为多聚体发挥作用。
