Mauser Amy, Holley-Guthrie Elizabeth, Zanation Adam, Yarborough Wendall, Kaufmann William, Klingelhutz Aloysius, Seaman William T, Kenney Shannon
Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7295, USA.
J Virol. 2002 Dec;76(24):12543-52. doi: 10.1128/jvi.76.24.12543-12552.2002.
The Epstein-Barr virus (EBV) immediate-early protein BZLF1 mediates the switch between the latent and lytic forms of EBV infection and has been previously shown to induce a G(1)/S block in cell cycle progression in some cell types. To examine the effect of BZLF1 on cellular gene expression, we performed microarray analysis on telomerase-immortalized human keratinocytes that were mock infected or infected with a control adenovirus vector (AdLacZ) or a vector expressing the EBV BZLF1 protein (AdBZLF1). Cellular genes activated by BZLF1 expression included E2F-1, cyclin E, Cdc25A, and a number of other genes involved in cell cycle progression. Immunoblot analysis confirmed that BZLF1 induced expression of E2F-1, cyclin E, Cdc25A, and stem loop binding protein (a protein known to be primarily expressed during S phase) in telomerase-immortalized keratinocytes. Similarly, BZLF1 increased expression of E2F-1, cyclin E, and stem loop binding protein (SLBP) in primary tonsil keratinocytes. In contrast, BZLF1 did not induce E2F-1 expression in normal human fibroblasts. Cell cycle analysis revealed that while BZLF1 dramatically blocked G(1)/S progression in normal human fibroblasts, it did not significantly affect cell cycle progression in primary human tonsil keratinocytes. Furthermore, in EBV-infected gastric carcinoma cells, the BZLF1-positive cells had an increased number of cells in S phase compared to the BZLF1-negative cells. Thus, in certain cell types (but not others), BZLF1 enhances expression of cellular proteins associated with cell cycle progression, which suggests that an S-phase-like environment may be advantageous for efficient lytic EBV replication in some cell types.
爱泼斯坦-巴尔病毒（EBV）即刻早期蛋白BZLF1介导EBV感染的潜伏形式与裂解形式之间的转换，并且先前已表明它在某些细胞类型中可诱导细胞周期进程中的G(1)/S期阻滞。为了研究BZLF1对细胞基因表达的影响，我们对端粒酶永生化的人角质形成细胞进行了微阵列分析，这些细胞分别为 mock感染、感染对照腺病毒载体（AdLacZ）或表达EBV BZLF1蛋白的载体（AdBZLF1）。由BZLF1表达激活的细胞基因包括E2F-1、细胞周期蛋白E、Cdc25A以及其他一些参与细胞周期进程的基因。免疫印迹分析证实，BZLF1在端粒酶永生化的角质形成细胞中诱导了E2F-1、细胞周期蛋白E、Cdc25A和茎环结合蛋白（一种已知主要在S期表达的蛋白）的表达。同样，BZLF1在原代扁桃体角质形成细胞中增加了E2F-1、细胞周期蛋白E和茎环结合蛋白（SLBP）的表达。相比之下，BZLF1在正常人成纤维细胞中未诱导E2F-1表达。细胞周期分析显示，虽然BZLF1显著阻断了正常人成纤维细胞中的G(1)/S期进程，但它对原代人扁桃体角质形成细胞的细胞周期进程没有显著影响。此外，在EBV感染的胃癌细胞中，与BZLF1阴性细胞相比，BZLF1阳性细胞的S期细胞数量增加。因此，在某些细胞类型（但不是其他细胞类型）中，BZLF1增强了与细胞周期进程相关的细胞蛋白的表达，这表明类似S期的环境可能有利于EBV在某些细胞类型中高效地进行裂解复制。
