Pearson G R, Luka J, Petti L, Sample J, Birkenbach M, Braun D, Kieff E
Virology. 1987 Sep;160(1):151-61. doi: 10.1016/0042-6822(87)90055-9.
When the latent Epstein-Barr virus (EBV) genome in B95-8 cells is induced into a replicative phase, two abundant early RNAs are transcribed rightward from the EBV BamHI H DNA fragment into BamHI F. Analysis of cDNA clones prepared from the RNA of cells replicating EBV revealed that both RNAs contain the BHRF1 open reading frame. Part of BHRF1, cloned into a prokaryotic fusion protein expression vector, expressed a fusion protein in Escherichia coli and the purified fusion protein was used to generate a monoclonal antibody against BHRF1. This antibody was then employed to characterize the protein encoded by BHRF1 in cells replicating EBV. The monoclonal antibody reacted with a 17-kDa protein component of the restricted early antigen (EA) complex. The distribution of the protein in cells was similar to that noted when sera from patients with African Burkitt's lymphoma were used to stain these cells. The protein was synthesized before the major 47-56 kDa protein associated with the diffuse component of EA in superinfected Raji cells. All human sera containing antibodies to EA as determined by immunofluorescence (IF) reacted with the protein as did some sera determined to be anti-VCA positive and anti-EA negative by IF. The predicted amino acid sequence of the protein has characteristics which suggest that it is a membrane protein. It also has significant homology with both the anchor region of polyoma middle T antigen and with the predicted protein product of the bcl-2 mRNA activated by the 14/18 chromosome translocation characteristic of follicular lymphomas. This latter homology is extensive and colinear, suggesting common evolution and function. However, neither a mRNA which could efficiently translate the BHRF1 protein nor the BHRF1 protein could be detected in latently infected cells. Thus, the bcl-2 predicted protein is similar to an EBV protein synthesized in the early phase of virus infection.
当B95 - 8细胞中潜伏的爱泼斯坦 - 巴尔病毒（EBV）基因组被诱导进入复制阶段时，从EBV BamHI H DNA片段向右转录出两种丰富的早期RNA，进入BamHI F。对从复制EBV的细胞RNA制备的cDNA克隆进行分析发现，这两种RNA都包含BHRF1开放阅读框。将BHRF1的一部分克隆到原核融合蛋白表达载体中，在大肠杆菌中表达了一种融合蛋白，纯化后的融合蛋白用于制备抗BHRF1单克隆抗体。然后使用该抗体来鉴定在复制EBV的细胞中由BHRF1编码的蛋白质。该单克隆抗体与受限早期抗原（EA）复合物的一种17 kDa蛋白质成分发生反应。该蛋白质在细胞中的分布与用非洲伯基特淋巴瘤患者血清对这些细胞进行染色时观察到的分布相似。在超感染的拉吉细胞中，该蛋白质在与EA弥漫成分相关的主要47 - 56 kDa蛋白质之前合成。通过免疫荧光（IF）测定含有抗EA抗体的所有人血清都与该蛋白质发生反应，一些通过IF测定为抗VCA阳性和抗EA阴性的血清也如此。该蛋白质的预测氨基酸序列具有表明它是一种膜蛋白的特征。它还与多瘤中间T抗原的锚定区域以及由滤泡性淋巴瘤特有的14/18号染色体易位激活的bcl - 2 mRNA的预测蛋白产物具有显著同源性。后一种同源性广泛且共线，表明有共同的进化和功能。然而，在潜伏感染的细胞中既未检测到能够有效翻译BHRF1蛋白的mRNA，也未检测到BHRF1蛋白。因此，bcl - 2预测蛋白类似于在病毒感染早期合成的一种EBV蛋白。
