Epstein-Barr virus nuclear protein EBNA3C is required for cell cycle progression and growth maintenance of lymphoblastoid cells
Epstein-Barr virus nuclear protein EBNA3C is required for cell cycle progression and growth maintenance of lymphoblastoid cells
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DOI：
10.1073/pnas.0604919104
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发表时间：
2006-12-19
影响因子：
11.1
通讯作者：
Takada, Kenzo
中科院分区：
文献类型：
--
作者：
Maruo, Seiji;Wu, Yi;Takada, Kenzo
EB病毒（EBV）感染将原代人B细胞转化为持续增殖的淋巴母细胞样细胞系（LCL）。为了研究EBV核抗原（EBNA）3C在LCL增殖中的作用，我们建立了用EBV重组体感染的LCL，所述EBV重组体表达EBNA 3C，其C-末端融合至4-羟基他莫昔芬（4 HT）依赖性突变型雌激素受体E3 C-HT。在4 HT存在下，LCL表达E3 C-HT蛋白，并像WT LCL一样生长。当E3 C-HT EBV感染的LCL转移到无4 HT的培养基中时，E3 C-HT蛋白缓慢消失，LCL逐渐停止生长。来自转染到E3 C-HT LCL中的oriP质粒的WT EBNA 3C表达保护LCL免于在不含4 HT的培养基中的生长停滞，而EBNA 3A或EBNA 3B的表达则没有。其他EBNA蛋白和LMP 1、CD 21、CD 23和c-myc的表达不受EBNA 3C失活的影响。然而，EBNA 3C失活导致p16（INK 4A）的积累，视网膜母细胞瘤蛋白过度磷酸化形式的减少，以及S或G（2）/M期细胞比例的减少。这些结果表明EBNA 3C在细胞周期进程和LCL的生长维持中具有重要作用。
Epstein-Barr virus (EBV) infection converts primary human B cells into continuously proliferating lymphoblastoid cell lines (LCLs). To examine the role of EBV nuclear antigen (EBNA) 3C in the proliferation of LCLs, we established LCLs infected with an EBV recombinant that expresses EBNA3C with a C-terminal fusion to a 4-hydroxytamoxifen (4HT)-dependent mutant estrogen receptor, E3C-HT. In the presence of 4HT, LCLs expressed the E3C-HT protein and grew like WT LCLs. When E3C-HT EBV-infected LCLs were transferred to medium without 4HT, E3C-HT protein slowly disappeared, and the LCLs gradually ceased growing. WT EBNA3C expression from an oriP plasmid transfected into E3C-HT LCLs protected the LCLs from growth arrest in medium without 4HT, whereas expression of EBNA3A or EBNA3B did not. The expression of other EBNA proteins and of LMP1, CD21, CD23, and c-myc was unaffected by EBNA3C inactivation. However, EBNA3C inactivation resulted in the accumulation of p16(INK4A), a decrease in the hyper-phosphorylated form of the retinoblastoma protein, and a decrease in the proportion of cells in S or G(2)/M phase. These results indicate that EBNA3C has an essential role in cell cycle progression and the growth maintenance of LCLs.