Liu R, Zhao X, Gurney T A, Landau N R
Aaron Diamond AIDS Research Center, New York, New York 10016, USA.
AIDS Res Hum Retroviruses. 1998 Nov 20;14(17):1509-19. doi: 10.1089/aid.1998.14.1509.
Two promoters for the CCR5 gene, termed Pu and Pd, corresponding to the upstream and downstream initiation sites, respectively, have been described. We show here that the proximal promoter, Pd, is used two- to fivefold more frequently than Pu in primary activated T cells and in the transformed T cell line PM1. Because of its importance in CCR5 transcription we characterized the transcriptional activity of this promoter. Pd contains a pair of consensus TATA elements (nt -19 and -31) and several potential regulatory elements and transcription factor-binding sites, including those for STAT, NF-kappaB, AP-1, NF-AT, and CD28RE. Using a transfected reporter vector, we found the promoter to be highly active and cell type specific. By 5' deletion analysis, the minimal CCR5 promoter was localized to a 225-nucleotide region (nt -189 to +36). This region contained the two TATA elements, a CD28RE consensus sequence, an AP-1-binding site, and two STAT-binding sites. The 1.9-kb intron appeared to have a negative influence on reporter gene activity, suggesting the presence of a negative element in this region. In addition, an upstream negative element was detected in the region nt -988 to -588. Mutagenesis of the TATA elements, of the NF-kappaB-, and AP-1-, and STAT-binding sites, and of the CD28RE indicated the importance of each of these in transcription. Finally, the NF-kappaB/Rel family member, p65(RelA), was a potent activator of the CCR5 promoter.
已描述了CCR5基因的两个启动子，分别称为Pu和Pd，它们分别对应于上游和下游起始位点。我们在此表明，在原代活化T细胞和转化的T细胞系PM1中，近端启动子Pd的使用频率比Pu高两到五倍。由于其在CCR5转录中的重要性，我们对该启动子的转录活性进行了表征。Pd包含一对共有TATA元件（核苷酸-19和-31）以及几个潜在的调控元件和转录因子结合位点，包括STAT、NF-κB、AP-1、NF-AT和CD28RE的结合位点。使用转染的报告载体，我们发现该启动子具有高活性且具有细胞类型特异性。通过5'缺失分析，最小的CCR5启动子定位于一个225个核苷酸的区域（核苷酸-189至+36）。该区域包含两个TATA元件、一个CD28RE共有序列、一个AP-1结合位点和两个STAT结合位点。1.9 kb的内含子似乎对报告基因活性有负面影响，表明该区域存在一个负调控元件。此外，在核苷酸-988至-588区域检测到一个上游负调控元件。对TATA元件、NF-κB、AP-1和STAT结合位点以及CD28RE进行诱变表明了它们各自在转录中的重要性。最后，NF-κB/Rel家族成员p65(RelA)是CCR5启动子的有效激活剂。
