Smith P R, Griffin B E
Department of Virology, Royal Postgraduate Medical School, University of London, United Kingdom.
J Virol. 1992 Feb;66(2):706-14. doi: 10.1128/JVI.66.2.706-714.1992.
Transcriptional expression of the Epstein-Barr virus (EBV) genome has been shown to differ markedly between nasopharyngeal carcinoma (NPC) cells and latent B-cell lines, with a more limited pattern of gene expression seen in NPC. EBNA-1 is the only nuclear antigen so far detected in both NPC and Burkitt's lymphoma cells. We found previously that in a human NPC tumor passaged in nude mice, designated C15, the EBNA-1 mRNA contained a novel splice site in the BamHI Q region of EBV which had not previously been described for B-cell lines. This lies within a region of the EBV genome to which EBNA-1 binds. Here, we further characterize the 5' region of EBNA-1 transcripts and identify two splicing patterns in C15 cells; we show that they are derived from a common promoter region in the BamHI F region of the viral genome. We also demonstrate that this region can function to initiate transcription of the chloramphenicol acetyltransferase gene in epithelial cells and that the promoter region is only partially methylated at CpG sites in the tumor. In contrast, a B-lymphoblastoid cell line derived from C15 uses a conventional promoter in BamHI-C/W for expression of EBNA-1.
爱泼斯坦-巴尔病毒（EBV）基因组的转录表达在鼻咽癌（NPC）细胞和潜伏性B细胞系之间已显示出显著差异，在NPC中观察到的基因表达模式更为有限。EBNA-1是迄今为止在NPC和伯基特淋巴瘤细胞中均检测到的唯一核抗原。我们先前发现，在裸鼠中传代的人NPC肿瘤（命名为C15）中，EBNA-1 mRNA在EBV的BamHI Q区域含有一个新的剪接位点，这在B细胞系中以前未曾描述过。这位于EBNA-1结合的EBV基因组区域内。在此，我们进一步对EBNA-1转录本的5'区域进行表征，并在C15细胞中鉴定出两种剪接模式；我们表明它们源自病毒基因组BamHI F区域中的一个共同启动子区域。我们还证明该区域可在上皮细胞中启动氯霉素乙酰转移酶基因的转录，并且该启动子区域在肿瘤的CpG位点仅部分甲基化。相比之下，源自C15的B淋巴母细胞系在BamHI-C/W中使用常规启动子来表达EBNA-1。
