Zhi Y, Sciabica K S, Sandri-Goldin R M
Department of Microbiology and Molecular Genetics, University of California, Irvine, California 92697-4025, USA.
Virology. 1999 May 10;257(2):341-51. doi: 10.1006/viro.1999.9698.
The herpes simplex virus type 1 (HSV-1) regulatory protein ICP27 is a nuclear phosphoprotein required for viral lytic infection, which acts partly at the posttranscriptional level to affect RNA processing and export. In the present study, we show that ICP27 can interact with itself in vivo. Immunofluorescent staining of cells expressing both an ICP27 mutant with a deletion of the major nuclear localization signal and wild-type ICP27 showed that the mutant protein was efficiently imported into the nucleus in the majority of the cotransfected cells, suggesting heterodimer formation between the wild-type and mutant proteins. Coimmunoprecipitation experiments using epitope-tagged wild-type ICP27 and a series of ICP27 mutants with deletions and insertions in important functional regions of the protein revealed that the C-terminal cysteine-histidine-rich zinc-finger-like region of ICP27 was required for the self-association. Furthermore the self-association was also shown in yeast using two-hybrid assays, and again, an intact C-terminal zinc-finger-like region was required for the interaction. This study provides biochemical evidence that ICP27 may function as a multimer in infected cells.
单纯疱疹病毒1型（HSV-1）调节蛋白ICP27是病毒裂解感染所需的一种核磷蛋白，它部分在转录后水平发挥作用，影响RNA的加工和输出。在本研究中，我们发现ICP27在体内可与自身相互作用。对同时表达缺失主要核定位信号的ICP27突变体和野生型ICP27的细胞进行免疫荧光染色，结果显示，在大多数共转染细胞中，突变蛋白能有效导入细胞核，这表明野生型和突变型蛋白之间形成了异二聚体。使用表位标记的野生型ICP27和一系列在该蛋白重要功能区域有缺失和插入的ICP27突变体进行的共免疫沉淀实验表明，ICP27的C端富含半胱氨酸-组氨酸的锌指样区域是自我缔合所必需的。此外，利用酵母双杂交实验也在酵母中显示了自我缔合，同样，相互作用需要完整的C端锌指样区域。本研究提供了生化证据，表明ICP27在受感染细胞中可能作为多聚体发挥作用。
