Chen M R, Yang J F, Wu C W, Middeldorp J M, Chen J Y
Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei.
J Biomed Sci. 1998;5(3):173-9. doi: 10.1007/BF02253466.
Epstein-Barr virus (EBV) nuclear antigen-1 (EBNA-1) is a protein expressed constitutively during EBV latency. It is required to support the replication of the EBV genome once per cell cycle via the latent origin of replication, oriP. EBNA-1 also can activate transcription through binding to the family repeats of oriP. We wished to identify candidate cellular protein(s) that may interact with EBNA-1 and mediate these functions. A 32-kd protein was co-immunoprecipitated with EBNA-1 from 293 cells using a monoclonal antibody EBNA.OT1x. The regions of EBNA-1 which interact with this protein were studied using two deletion clones and mapped to EBNA-1 residues 1-102 and 325-357. Deletion of this region was shown previously in a mutant of EBNA-1 which had dominant-negative effects on both DNA replication and transactivation assays. The 32-kd protein was found to react with a polyclonal antiserum against P32/TAP (HIV Tat associated protein), which is known to interact with other RNA binding proteins and the RNA splicing factor SF2. The function of P32 was therefore proposed to involve RNA processing. In addition, this molecule was recently identified as hyaluronectin, which binds hyaluronic acid. Because several reports documented that intracellular hyaluronic acid can potentially affect cell proliferation, the association between EBNA-1 and P32/TAP/hyaluronectin may help the maintenance of episomal viral DNA within proliferating cells.
爱泼斯坦-巴尔病毒（EBV）核抗原1（EBNA-1）是一种在EBV潜伏期间持续表达的蛋白质。它通过潜伏性复制起点oriP，在每个细胞周期中支持EBV基因组复制一次。EBNA-1还可通过与oriP的家族重复序列结合来激活转录。我们希望鉴定出可能与EBNA-1相互作用并介导这些功能的候选细胞蛋白。使用单克隆抗体EBNA.OT1x从293细胞中与EBNA-1共免疫沉淀出一种32-kd的蛋白质。使用两个缺失克隆研究了EBNA-1与该蛋白质相互作用的区域，并将其定位到EBNA-1的1-102和325-357位残基。该区域的缺失先前在EBNA-1的一个突变体中显示，该突变体对DNA复制和反式激活测定均具有显性负效应。发现该32-kd蛋白质与针对P32/TAP（HIV Tat相关蛋白）的多克隆抗血清发生反应，已知该蛋白与其他RNA结合蛋白和RNA剪接因子SF2相互作用。因此推测P32的功能涉及RNA加工。此外，该分子最近被鉴定为透明质酸结合蛋白，可结合透明质酸。由于几份报告记录了细胞内透明质酸可能影响细胞增殖，EBNA-1与P32/TAP/透明质酸结合蛋白之间的关联可能有助于在增殖细胞中维持游离病毒DNA。
