Epstein-Barr virus nuclear antigens 3C and 3A maintain lymphoblastoid cell growth by repressing p16INK4A and p14ARF expression
Epstein-Barr virus nuclear antigens 3C and 3A maintain lymphoblastoid cell growth by repressing p16INK4A and p14ARF expression
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DOI：
10.1073/pnas.1019599108
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发表时间：
2011-02-01
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;Zhao, Bo;Takada, Kenzo
eb病毒（EBV）核抗原3C （EBNA3C）和EBNA3A都是EBV将人原代B淋巴细胞转化为持续增殖的淋巴母细胞系（LCL）和维持LCL生长所必需的。我们现在发现EBNA3C和EBNA3A的基本作用是抑制p16（INK4A）和p14（ARF）。在缺乏EBNA3C或EBNA3A的情况下，p16（INK4A）和p14（ARF）表达增加，细胞生长停止。EBNA3C失活没有改变p16（INK4A）启动子CpG甲基化，但相对于静止的B细胞，降低了已经很低的H3K27me3，并增加了H3K4me3和h3乙酰化，将EBNA3C失活与转录增加相关的组蛋白修饰联系起来。重要的是，p16（INK4A）或p14（ARF）的敲低部分地挽救了EBNA3C或EBNA3A失活诱导的LCL生长停滞，以及挽救的LCL生长的敲低，证实了p16（INK4A）和p14（ARF）在EBNA3C或EBNA3A失活后LCL生长停滞中的核心作用。此外，阻断p16（INK4A）和p14（ARF）对人乳头瘤病毒16型E7和E6表达的pRb和p53的影响，在EBNA3C或EBNA3A失活后持续LCL生长。这些数据表明，EBNA3C和EBNA3A联合抑制CDKN2A p16（INK4A）和p14（ARF）对LCL生长至关重要。
Epstein-Barr virus (EBV) nuclear antigen 3C (EBNA3C) and EBNA3A are each essential for EBV conversion of primary human B lymphocytes into continuously proliferating lymphoblast cell lines (LCLs) and for maintaining LCL growth. We now find that EBNA3C and EBNA3A's essential roles are to repress p16(INK4A) and p14(ARF). In the absence of EBNA3C or EBNA3A, p16(INK4A) and p14(ARF) expression increased and cell growth ceased. EBNA3C inactivation did not alter p16(INK4A) promoter CpG methylation, but reduced already low H3K27me3, relative to resting B cells, and increased H3K4me3 and H3-acetylation, linking EBNA3C inactivation to histone modifications associated with increased transcription. Importantly, knockdown of p16(INK4A) or p14(ARF) partially rescued LCLs from EBNA3C or EBNA3A inactivation-induced growth arrest and knockdown of both rescued LCL growth, confirming central roles for p16(INK4A) and p14(ARF) in LCL growth arrest following EBNA3C or EBNA3A inactivation. Moreover, blockade of p16(INK4A) and p14(ARF) effects on pRb and p53 by human papilloma virus type 16 E7 and E6 expression, sustained LCL growth after EBNA3C or EBNA3A inactivation. These data indicate that EBNA3C and EBNA3A joint repression of CDKN2A p16(INK4A) and p14(ARF) is essential for LCL growth.