Urier G, Buisson M, Chambard P, Sergeant A
UMR 13 ENS-CNRS, Ecole Normale Superieure de Lyon, France.
EMBO J. 1989 May;8(5):1447-53. doi: 10.1002/j.1460-2075.1989.tb03527.x.
When expressed in Epstein-Barr virus (EBV) latently infected B cells, the EBV early protein EB1 trans-activates as many EBV early genes as does TPA. Several EB1 responsive elements (ZRE) have been identified in EBV early promoters and are located at relatively short distances from the TATA box. One of them (ZRE-M) overlaps with a consensus TPA responsive element (TRE) defined as an AP-1/c-jun/c-fos binding site and is located in an EBV promoter controlling the expression of the post-transcriptional activator EB2. Another (ZREZ) is located in the promoter controlling the expression of EB1 and does not respond to TPA. These two ZREs have no apparent sequence homology. Although EB1 activates transcription from the AP-1 enhancer sequence and from the ZREZ, the activation is severely impaired by distance, suggesting that EB1 is more likely to be a promoter factor than an enhancer factor. These properties also suggest that EB1 is not functionally related to c-jun and c-fos. However, since EB1 can activate transcription from AP-1 binding sites when properly positioned, the role of this factor in the oncogenic properties of EBV should be considered.
当在爱泼斯坦-巴尔病毒（EBV）潜伏感染的B细胞中表达时，EBV早期蛋白EB1与佛波酯（TPA）一样能反式激活许多EBV早期基因。在EBV早期启动子中已鉴定出几个EB1反应元件（ZRE），它们位于距TATA框相对较短的距离处。其中一个（ZRE-M）与定义为AP-1/c-jun/c-fos结合位点的共有TPA反应元件（TRE）重叠，且位于控制转录后激活因子EB2表达的EBV启动子中。另一个（ZRE-Z）位于控制EB1表达的启动子中，且对TPA无反应。这两个ZRE没有明显的序列同源性。虽然EB1能激活来自AP-1增强子序列和ZRE-Z的转录，但这种激活会因距离而严重受损，这表明EB1更可能是一种启动子因子而非增强子因子。这些特性还表明EB1在功能上与c-jun和c-fos无关。然而，由于EB1在适当定位时能激活来自AP-1结合位点的转录，因此应考虑该因子在EBV致癌特性中的作用。
