Romano-Spica V, Georgiou P, Suzuki H, Papas T S, Bhat N K
Laboratory of Molecular Oncology, National Cancer Institute, Frederick, MD 21702.
J Immunol. 1995 Mar 15;154(6):2724-32.
The ETS1 gene encodes a sequence-specific transcription factor binding to purine-rich DNA sequences (-GGAA-) present in the transcriptional regulatory regions of many cellular and viral promoters/enhancers, including many lymphokine genes. The ETS1 gene is expressed at high levels in resting T cells and at very low levels after T cell activation, suggesting it may suppress the expression of genes induced during T cell activation. To find out if ETS1 regulates expression of the IL-2 gene, we have ectopically expressed antisense (AS) ETS1 in Jurkat T cells to block the formation of ETS1 proteins. AS ETS1 transfectants produce higher levels of IL-2 compared with sense ETS1 transfectants. Expression of ETS1 DNA binding domain in Jurkat T cells also decreased the production of IL-2. In AS ETS1 transfectants, IL-2 formation was completely inhibited by cyclosporin A and FK590. The IL-2 promoter linked to a chloramphenicol acetyl transferase reporter gene has high activity in AS ETS1 transfectants, indicating that increased IL-2 production seems to be a result of transcriptional induction. Taken together, these results suggest the possibility that ETS1 may act as a negative regulator of IL-2 gene transcription and provide a rational approach toward engineering the endogenous expression of IL-2 in T cells.
ETS1基因编码一种序列特异性转录因子，它能与许多细胞和病毒启动子/增强子（包括许多淋巴因子基因）转录调控区域中存在的富含嘌呤的DNA序列（-GGAA-）结合。ETS1基因在静止T细胞中高水平表达，而在T细胞激活后表达水平极低，这表明它可能抑制T细胞激活过程中诱导基因的表达。为了确定ETS1是否调节IL-2基因的表达，我们在Jurkat T细胞中异位表达反义（AS）ETS1以阻断ETS1蛋白的形成。与正义ETS1转染子相比，AS ETS1转染子产生更高水平的IL-2。在Jurkat T细胞中表达ETS1 DNA结合结构域也降低了IL-2的产生。在AS ETS1转染子中，环孢菌素A和FK590完全抑制了IL-2的形成。与氯霉素乙酰转移酶报告基因相连的IL-2启动子在AS ETS1转染子中具有高活性，这表明IL-2产生增加似乎是转录诱导的结果。综上所述，这些结果提示ETS1可能作为IL-2基因转录的负调节因子，并为在T细胞中工程化内源性IL-2表达提供了一种合理的方法。
