Tesmer V M, Rajadhyaksha A, Babin J, Bina M
Department of Chemistry, Purdue University, West Lafayette, IN 47907-1393.
Proc Natl Acad Sci U S A. 1993 Aug 1;90(15):7298-302. doi: 10.1073/pnas.90.15.7298.
An upstream control region in the long terminal repeat (LTR) of human immunodeficiency virus type 1 (HIV-1) includes a potential negative regulatory element (NRE1). Cotransfecting multimers of a sequence spanning this element with an LTR-CAT construct produced an increase in chloramphenicol acetyltransferase (CAT) activity in Jurkat and HepG2 cells, providing further evidence and support for the existence of an NRE. In screening experiments aimed at identifying those factors that regulate HIV-1 transcription through interactions with the NRE1 region, we isolated a cDNA for NF-IL6. Previous studies have shown that NF-IL6 is a key nuclear factor that activates gene expression in response to interleukin 6. By methylation interference analysis, we have localized the NF-IL6 binding site within the NRE1 region and found that it overlaps an E box that has previously been implicated as the binding element for a negative regulator of HIV-1 expression. Through a database search, we identified an additional consensus binding sequence for NF-IL6 in the LTR of many HIV-1 variants and found that over this sequence, purified NF-IL6 can produce an extended footprint that overlaps one of the binding sites for NF-kappa B. A product of the nf-il6 gene activated transcription from several LTR-CAT constructs in transient transfection assays. Thus, NF-IL6 could play a central role in the control of HIV-1 gene expression and this protein might be a key mediator in signaling pathways where HIV-1 is activated by interleukin 6.
人类免疫缺陷病毒1型（HIV-1）长末端重复序列（LTR）中的一个上游调控区域包含一个潜在的负调控元件（NRE1）。将跨越该元件的序列多聚体与LTR-CAT构建体共转染，可使Jurkat细胞和HepG2细胞中的氯霉素乙酰转移酶（CAT）活性增加，这为NRE的存在提供了进一步的证据和支持。在旨在鉴定那些通过与NRE1区域相互作用来调节HIV-1转录的因子的筛选实验中，我们分离出了NF-IL6的cDNA。先前的研究表明，NF-IL6是一种关键的核因子，可响应白细胞介素6激活基因表达。通过甲基化干扰分析，我们已将NF-IL6结合位点定位在NRE1区域内，并发现它与一个E盒重叠，该E盒先前被认为是HIV-1表达负调控因子的结合元件。通过数据库搜索，我们在许多HIV-1变体的LTR中鉴定出了另一个NF-IL6共有结合序列，并发现纯化的NF-IL6在该序列上可产生一个扩展的足迹，该足迹与NF-κB的一个结合位点重叠。在瞬时转染实验中，nf-il6基因的一个产物激活了几个LTR-CAT构建体的转录。因此，NF-IL6可能在HIV-1基因表达的控制中起核心作用，并且该蛋白可能是HIV-1被白细胞介素6激活的信号通路中的关键介质。
