Taylor K A, Wetzel S, Lyles D S, Pollok B A
Department of Microbiology and Immunology, Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, North Carolina 27157-1064.
J Virol. 1994 Oct;68(10):6421-31. doi: 10.1128/JVI.68.10.6421-6431.1994.
The use of different viral promoters for the expression of the EBNA1 gene product appears to be a critical step in the regulation of Epstein-Barr virus latent gene expression and may reflect the extent of differentiation of B-cell hosts. Low-passage Burkitt lymphoma cell lines resemble immature B cells in that they express CD10 (CALLA) and do not express B-cell activation antigens. In these cells, transcription from a promoter located in the BamHI F fragment of the viral genome results in the exclusive expression of EBNA1, referred to as the latency I pattern of viral gene expression. In contrast, high-passage Burkitt lymphoma cells and lymphoblastoid cell lines resemble activated B cells in that they do not express CD10 but do express activation antigens such as CD23. In these cells, the use of two promoters located in the BamHI W and C fragments of the viral genome leads to the expression of all six EBNA gene products (latency III). We have found that four human B-cell lines, DB, LBW2, LBW14, and Josh 7, stably express a pattern of B-cell differentiation antigens intermediate between those found in latency I and latency III cell lines and characterized by the coexpression of CD10 and CD23. The pattern of EBNA1 promoter usage in these cell lines was examined to determine whether their intermediate cellular phenotype was reflected in their patterns of viral gene expression. DB, LBW2, and LBW14 utilize both the BamHI F promoter region and BamHI W promoter region to transcribe the EBNA1 gene. This stable pattern of mixed promoter usage for the expression of the EBNA gene products in B cells has not previously been described. In addition, these three B-cell lines expressed lower levels of the viral latent gene product EBNA2 than those typically observed in latency III cells. The lower levels of activation of viral and cellular promoters known to be regulated by EBNA2 also correlated with the reduced levels of EBNA2 expression in these cells. These included the viral LMP1 and LMP2A promoters and the cellular CD23B promoter. The fourth B-cell line, Josh 7, expressed EBNA1 mRNAs derived from both the BamHI W promoter and BamHI C promoter, similar to latency III cells. The intermediate cellular phenotype in Josh 7 cells appeared to be due, in part, to a deficiency in the expression of viral LMP1.(ABSTRACT TRUNCATED AT 400 WORDS)
使用不同的病毒启动子来表达EBNA1基因产物似乎是调控爱泼斯坦 - 巴尔病毒潜伏基因表达的关键步骤，并且可能反映B细胞宿主的分化程度。低传代的伯基特淋巴瘤细胞系类似于未成熟B细胞，因为它们表达CD10（CALLA）且不表达B细胞活化抗原。在这些细胞中，来自病毒基因组BamHI F片段中一个启动子的转录导致EBNA1的特异性表达，这被称为病毒基因表达的潜伏I模式。相反，高传代的伯基特淋巴瘤细胞和淋巴母细胞系类似于活化的B细胞，因为它们不表达CD10但表达活化抗原如CD23。在这些细胞中，使用位于病毒基因组BamHI W和C片段中的两个启动子导致所有六种EBNA基因产物的表达（潜伏III）。我们发现四个人B细胞系，DB、LBW2、LBW14和Josh 7，稳定表达一种B细胞分化抗原模式，该模式介于潜伏I和潜伏III细胞系中发现的模式之间，其特征是CD10和CD23的共表达。检测了这些细胞系中EBNA1启动子的使用模式，以确定它们中间的细胞表型是否反映在它们的病毒基因表达模式中。DB、LBW2和LBW14利用BamHI F启动子区域和BamHI W启动子区域来转录EBNA1基因。这种在B细胞中用于表达EBNA基因产物的混合启动子使用的稳定模式以前尚未被描述。此外，这三个B细胞系表达的病毒潜伏基因产物EBNA2水平低于在潜伏III细胞中通常观察到的水平。已知受EBNA2调控的病毒和细胞启动子的较低活化水平也与这些细胞中EBNA2表达水平的降低相关。这些包括病毒LMP1和LMP2A启动子以及细胞CD23B启动子。第四个B细胞系Josh 7表达源自BamHI W启动子和BamHI C启动子的EBNA1 mRNA，类似于潜伏III细胞。Josh 7细胞中的中间细胞表型似乎部分归因于病毒LMP1表达的缺陷。（摘要截短至400字）
