EPSTEIN-BARR-VIRUS NUCLEAR ANTIGEN-2 TRANSACTIVATES THE LONG TERMINAL REPEAT OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1
EPSTEIN-BARR-VIRUS NUCLEAR ANTIGEN-2 TRANSACTIVATES THE LONG TERMINAL REPEAT OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1
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DOI：
10.1128/jvi.67.5.2853-2861.1993
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发表时间：
1993-05-01
影响因子：
5.4
通讯作者：
VENUTA, S
中科院分区：
文献类型：
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作者：
SCALA, G;QUINTO, I;VENUTA, S
人类免疫缺陷病毒1型（HIV-1）感染的受试者显示出eb病毒感染的高发。这表明EBV可能作为影响HIV-1激活的辅助因子，并可能在艾滋病的进展中发挥主要作用。为了验证这一假设，我们产生了两个EBV阴性的人b细胞系，它们稳定地表达EBV的EBNA2基因。这些ebna2阳性细胞系被携带与氯霉素乙酰转移酶（CAT）基因融合的HIV-1长末端重复序列（LTR）的野生型或缺失突变体的质粒瞬时转染。在表达EBNA2的细胞中，HIV-1 LTR的激活始终高于对照细胞，这表明EBNA2蛋白可能通过诱导核因子结合HIV-1顺式调控序列来激活HIV-1启动子。为了验证这种可能性，我们使用了基于cat的质粒，携带NF-kappaB （pNFA-CAT）、Sp1 （pSpA-CAT）、我们发现，HIV-1 LTR的NF-kappaB和Sp1区域的NF-kappaB和Sp1位点都是EBNA2转激活所必需的，NF-kappaB和Sp1位点的表达增加是由NF-kappaB样因子的诱导引起的。此外，用tar缺失的pTAR-CAT和表达tat的pAR-TAT质粒进行的实验表明，内源性tat样蛋白可以参与EBNA2介导的HIV-1 LTR的激活，并且EBNA2蛋白可以与病毒tat反激活子协同作用。用表达EBNA1、EBNA3和ebnaalp基因的质粒转染实验没有引起显著的HIV-1 LTR激活。由此可见，在检测的EBV潜伏基因中，EBNA2是唯一在HIV-1 LTR上有活性的EBV基因，在HeLa上皮细胞系中也观察到EBNA2的反激活功能，这表明EBV和HIV-1感染非b细胞可能导致HIV-1启动子激活。因此，EBV的特定基因产物EBNA2可以反激活HIV-1，并可能促进艾滋病的临床进展。
Human immunodeficiency virus type 1 (HIV-1)-infected subjects show a high incidence of Epstein-Barr virus (EBV) infection. This suggests that EBV may function as a cofactor that affects HIV-1 activation and may play a major role in the progression of AIDS. To test this hypothesis, we generated two EBV-negative human B-cell lines that stably express the EBNA2 gene of EBV. These EBNA2-positive cell lines were transiently transfected with plasmids that carry either the wild type or deletion mutants of the HIV-1 long terminal repeat (LTR) fused to the chloramphenicol acetyltransferase (CAT) gene. There was a consistently higher HIV-1 LTR activation in EBNA2-expressing cells than in control cells, which suggested that EBNA2 proteins could activate the HIV-1 promoter, possibly by inducing nuclear factors binding to HIV-1 cis-regulatory sequences. To test this possibility, we used CAT-based plasmids carrying deletions of the NF-kappaB (pNFA-CAT), Sp1 (pSpA-CAT), or TAR (pTAR-CAT) region of the HIV-1 LTR and retardation assays in which nuclear proteins from EBNA2-expressing cells were challenged with oligonucleotides encompassing the NF-kappaB or Sp1 region of the HIV-1 LTR. We found that both the NF-kappaB and the Sp1 sites of the HIV-1 LTR are necessary for EBNA2 transactivation and that increased expression resulted from the induction of NF-kappaB-like factors. Moreover, experiments with the TAR-deleted pTAR-CAT and with the tat-expressing pAR-TAT plasmids indicated that endogenous Tat-like proteins could participate in EBNA2-mediated activation of the HIV-1 LTR and that EBNA2 proteins can synergize with the viral tat transactivator. Transfection experiments with plasmids expressing the EBNA1, EBNA3, and EBNALP genes did not cause a significant HIV-1 LTR activation. Thus, it appears that among the latent EBV genes tested, EBNA2 was the only EBV gene active on the HIV-1 LTR. The transactivation function of EBNA2 was also observed in the HeLa epithelial cell line, which suggests that EBV and HIV-1 infection of non-B cells may result in HIV-1 promoter activation. Therefore, a specific gene product of EBV, EBNA2, can transactivate HIV-1 and possibly contribute to the clinical progression of AIDS.