Silencer Activity of NFATc2 in the Interleukin-12 Receptor β2 Proximal Promoter in Human T Helper Cells*
Silencer Activity of NFATc2 in the Interleukin-12 Receptor β2 Proximal Promoter in Human T Helper Cells*
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人类 T 辅助细胞中 IL-12 受体 β2 近端启动子中 NFATc2 的沉默活性*
DOI：
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发表时间：
2001
影响因子：
4.8
通讯作者：
E. Wierenga
中科院分区：
文献类型：
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作者：
J. V. van Rietschoten;H. Smits;Diederik van de Wetering;R. Westland;C. L. Verweij;M. den Hartog;E. Wierenga
白细胞介素12（IL-12）是激活的T细胞产生干扰素γ的有效增强剂。高亲和力IL-12受体（IL-12 R）是β1和β2亚基的异源二聚体。与更丰富的β1链相比，信号传导IL-12 R β2链的表达通常较低，并且可能是IL-12敏感性的限速因素。IL-12 R β2基因表达的调控机制尚不清楚。在表达IL-12 R β2的Jurkat细胞中进行的报告基因分析表明，从−151到−61的区域的截短废除了启动子活性。近端启动子区不包含典型的TATA盒，表明SP-1的作用。事实上，−63 SP-1共有位点的突变使转录降低了50%。电泳迁移率变动实验证实了SP-1和SP-3在该位点的结合。相反，-252到-192的截短增加了启动子活性。同样，激活T细胞的共有核因子在-206位点的突变使启动子活性增加了70%，表明该元件具有沉默活性。电泳迁移率变化实验与初级Th（T辅助细胞）细胞显示，在这个网站是敏感的环孢菌素A和supershift与抗NFATc 2在Th 1和Th 2细胞的一个特定的，T细胞受体诱导的复合物的形成。因此，环孢素A剂量依赖性地增加IL-12 R β2 mRNA表达。这些关于IL-12 R β2基因调控的第一批数据表明，TATA启动子较少，依赖于SP-1/SP-3转录因子，在-206处有一个负调控NFAT元件。该元件可能有助于Th细胞上IL-12 R β2表达的总体低水平。
Interleukin 12 (IL-12) is a potent enhancer of interferon γ production by activated T cells. The high-affinity IL-12 receptor (IL-12R) is a heterodimer of a β1 and a β2 subunit. Expression of the signaling IL-12Rβ2 chain is usually low, as compared with the more abundant β1 chain, and may be rate-limiting for IL-12 sensitivity. Little is known about the mechanisms controllingIL-12Rβ2 gene expression. Reporter gene assays in IL-12Rβ2-expressing Jurkat cells showed that truncation of the region from −151 to −61 abrogated promoter activity. The proximal promoter region does not contain a typical TATA box, suggesting a role for SP-1. Indeed, mutagenesis of the −63 SP-1 consensus site decreased transcription by 50%. Electrophoretic mobility shift experiments confirmed the binding of SP-1 and SP-3 at this site. In contrast, truncation of −252 to −192 increased promoter activity. Likewise, mutagenesis of the consensus nuclear factor of activated T cells site at −206 increased promoter activity by 70%, suggesting silencer activity of this element. Electrophoretic mobility shift experiments with primary Th (T helper) cells showed the formation of a specific, T-cell receptor-inducible complex at this site that is sensitive to cyclosporin A and supershifted with anti-NFATc2 in both Th1 and Th2 cells. Accordingly, cyclosporin A dose-dependently increased IL-12Rβ2 mRNA expression. These first data onIL-12Rβ2 gene regulation indicate a TATA-less promoter, depending on SP-1/SP-3 transcription factors, and a negative regulatory NFAT element at −206. This element may contribute to the overall low level of IL-12Rβ2 expression on Th cells.
影响因子：
56.9
作者：
SALGAME, P;ABRAMS, JS;BLOOM, BR
通讯作者：
BLOOM, BR
影响因子：
32.4
作者：
Ouyang, W;Ranganath, SH;Murphy, KM
通讯作者：
Murphy, KM
影响因子：
15.9
作者：
MANGER, B;HARDY, KJ;STOBO, JD
通讯作者：
STOBO, JD