Barry P A, Pratt-Lowe E, Peterlin B M, Luciw P A
Department of Medical Pathology, University of California, Davis 95616.
J Virol. 1990 Jun;64(6):2932-40. doi: 10.1128/JVI.64.6.2932-2940.1990.
Proteins encoded by a variety of DNA viruses activate gene expression from the promoter within the long terminal repeat (LTR) of the human immunodeficiency virus type 1 (HIV-1). The mechanism by which immediate-early (IE) gene products of human cytomegalovirus (CMV) activate expression from the HIV-1 LTR was examined in transient expression assays in cultures of human cells by using plasmids containing the LTR linked to the bacterial chloramphenicol acetyltransferase (CAT) gene and a plasmid expressing the CMV IE gene. Analysis of clustered site mutations within the HIV-1 LTR revealed that sequences from nucleotides -6 to +20 (relative to the start site of transcription) are critical for responsiveness to transactivation by CMV IE gene products. This region partially overlaps the trans-acting response element (+19 to +42) required for function of the HIV-1 transactivator. The CMV IE gene was shown to increase the steady-state levels of both prematurely terminated and full-length transcripts initiated within the LTR. These results support a model in which CMV IE gene products act through a specific regulatory element in the HIV-1 LTR to increase viral transcription.
多种DNA病毒编码的蛋白质可激活人类免疫缺陷病毒1型（HIV-1）长末端重复序列（LTR）内启动子的基因表达。在人类细胞培养物的瞬时表达试验中，通过使用含有与细菌氯霉素乙酰转移酶（CAT）基因相连的LTR的质粒和表达巨细胞病毒（CMV）立即早期（IE）基因的质粒，研究了CMV的IE基因产物激活HIV-1 LTR表达的机制。对HIV-1 LTR内的成簇位点突变进行分析发现，核苷酸-6至+20（相对于转录起始位点）的序列对于对CMV IE基因产物的反式激活反应至关重要。该区域部分重叠HIV-1反式激活因子功能所需的反式作用反应元件（+19至+42）。结果表明，CMV IE基因可增加LTR内起始的过早终止转录本和全长转录本的稳态水平。这些结果支持一种模型，即CMV IE基因产物通过HIV-1 LTR中的特定调控元件发挥作用，以增加病毒转录。
