Human immunodeficiency virus type 1 Vpr protein transactivation function: Mechanism and identification of domains involved
Human immunodeficiency virus type 1 Vpr protein transactivation function: Mechanism and identification of domains involved
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DOI：
10.1006/jmbi.1998.2206
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发表时间：
1998-12-11
影响因子：
5.6
通讯作者：
Cohen, EA
中科院分区：
文献类型：
--
作者：
Forget, J;Yao, XJ;Cohen, EA
人类免疫缺陷病毒1型（HIV-1）Vpr蛋白是一种病毒体相关蛋白，定位于感染细胞的细胞核中。研究表明，Vpr通过促进整合前复合物的核移位，促进艾滋病毒感染非分裂细胞（例如巨噬细胞）。最近，Vpr表达已显示诱导细胞在细胞周期的G2期的积累。我们以前曾报道，Vpr刺激报告基因表达的HIV-1长末端重复序列（LTR），以及从异源病毒启动子。然而，Vpr介导的反式激活的作用模式仍有待精确定义。我们在这里报告，对于恒定量的转染DNA，氯霉素乙酰转移酶（CAT）mRNA的水平增加Vpr表达细胞使用HIV-1或鼠白血病病毒（MLV）SL 3 -3 LTR-CAT报告构建体。此外，这种Vpr介导的反式激活需要启动子指导最低水平的基础表达。我们的诱变分析表明，Vpr介导的反式激活不依赖于蛋白质定位在细胞核中或包装在病毒体中的能力。有趣的是，所有的反式激活能力Vpr突变体仍然能够诱导细胞周期停滞。相反，反式激活缺陷突变体失去了介导细胞周期停滞的能力，这意味着这两个功能之间的功能关系。总的来说，我们的研究结果表明，Vpr介导的G2细胞周期阻滞创造了一个细胞环境，其中HIV-1 LTR在转录上更活跃。(C)北京：科学出版社.
The human immunodeficiency virus type 1 (HIV-1) Vpr protein is a virion-associated protein that localizes in the nucleus of infected cells. Vpr has been shown to facilitate HIV infection of non-dividing cells such as macrophages by contributing to the nuclear translocation of the pre-integration complex. More recently, Vpr expression has been shown to induce an accumulation of cells at the G2 phase of the cell-cycle. We have previously reported that Vpr stimulates reporter gene expression directed from the HIV-1 long terminal repeat (LTR) as well as from heterologous viral promoters. However, the mode of action of Vpr-mediated transactivation remains to be precisely defined. We report here that, for a constant amount of transfected DNA, the level of chloramphenicol acetyltransferase (CAT) mRNA is increased in Vpr-expressing cells using either HIV-1 or a murine leukemia virus (MLV) SL3-3 LTR-CAT reporter construct. Moreover, this Vpr-mediated transactivation requires that promoters direct a minimal level of basal expression. Our mutagenic analysis indicates that the transactivation mediated by Vpr is not dependent on the ability of the protein to localize in the nucleus or to be packaged in the virions. Interestingly, all transactivation-competent Vpr mutants were still able to induce a cell-cycle arrest. Conversely, transactivation-defective mutants lost the ability to mediate cell-cycle arrest, implying a functional relationship between these two functions. Overall, our results indicate that the G2 cell-cycle arrest mediated by Vpr creates a cellular environment where the HIV-1 LTR is transcriptionally more active. (C) 1998 Academic Press.