Cross S L, Halden N F, Lenardo M J, Leonard W J
Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, Bethesda, MD 20892.
Science. 1989 Apr 28;244(4903):466-9. doi: 10.1126/science.2497520.
The interleukin-2 receptor alpha (IL-2R alpha) chain gene contains a sequence similar to the immunoglobulin (Ig) kappa (kappa) enhancer NF-kappa B binding site. This site, which is bound by the nuclear protein, NF-kappa B, is critical for Ig kappa gene expression. The major T cell nuclear factor that binds to the IL-2R alpha site in vitro appears indistinguishable from NF-kappa B. NF-kappa B binds to IL-2R alpha and kappa sequences with similar affinities; however, only the kappa site potently activates transcription from heterologous promoters. Thus, high-affinity NF-kappa B binding in vitro cannot be equated with transcriptional activation in vivo. Mutation of the NF-kappa B binding site in the context of an IL-2 R alpha promoter construct markedly diminished promoter activity in human T cell lymphotropic virus type I (HTLV-I)-transformed MT-2 cells but not in phorbol myristate acetate-stimulated Jurkat T cells.
白细胞介素-2受体α（IL-2Rα）链基因包含一段与免疫球蛋白（Ig）κ（kappa）增强子NF-κB结合位点相似的序列。该位点由核蛋白NF-κB结合，对Igκ基因表达至关重要。体外与IL-2Rα位点结合的主要T细胞核因子似乎与NF-κB无法区分。NF-κB以相似的亲和力结合IL-2Rα和κ序列；然而，只有κ位点能有效激活异源启动子的转录。因此，体外高亲和力的NF-κB结合不能等同于体内的转录激活。在IL-2Rα启动子构建体背景下，NF-κB结合位点的突变显著降低了人T细胞嗜淋巴细胞病毒I型（HTLV-I）转化的MT-2细胞中的启动子活性，但在佛波酯肉豆蔻酸酯乙酸酯刺激的Jurkat T细胞中则没有。
