The interferon-stimulated response element and a kappa B site mediate synergistic induction of murine IP-10 gene transcription by IFN-gamma and TNF-alpha.
The interferon-stimulated response element and a kappa B site mediate synergistic induction of murine IP-10 gene transcription by IFN-gamma and TNF-alpha.
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DOI：
10.4049/jimmunol.154.10.5235
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发表时间：
1995-05
影响因子：
4.4
通讯作者：
Y. Ohmori;T. Hamilton
中科院分区：
文献类型：
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作者：
Y. Ohmori;T. Hamilton
本研究调查了 IFN-γ 和 TNF-α 之间合作促进 NIH 3T3 细胞中 IP-10 基因转录的机制。 IFN-γ协同增强TNF-α诱导的IP-10 mRNA水平，而TNF-α诱导的JE (MCP-1)或KC (GRO/MGSA) mRNA水平不受IFN-γ影响。 IFN-γ 和 TNF-α 之间的合作诱导 IP-10 mRNA 不依赖于从头蛋白质合成，并且至少部分由转录增加介导。对鼠 IP-10 基因转录起始位点侧翼的 243 bp 片段进行瞬时转染分析表明，两种刺激之间的协同作用取决于三个关键调控序列元件中至少两个的占据：一个 IFN 刺激反应元件 (ISRE) 和两个 kappa B 位点之一。 IFN-γ 和 TNF-α 独立激活核因子，能够分别与 ISRE 和 kappa B 位点发生特异性相互作用。 IFN-γ诱导两种ISRE结合复合物，其中一种与蛋白质合成无关，在刺激后15分钟内出现，并含有p91或信号转导子和转录激活剂（STAT）1。TNF-α仅诱导一种ISRE结合活性，该活性依赖于蛋白质合成。 TNF-α 还诱导由 NF-κ B1 (p50) 和 RelA (p65) 组成的 κ B 结合活性，而 IFN-γ 对 κ B 结合活性没有可检测到的影响。这些结果共同表明，IFN-γ和TNF-α对IP-10基因的高度协同转录激活涉及由两种刺激独立激活并结合到独立位点的因子之间的合作。
The present study investigates mechanisms involved in cooperation between IFN-gamma and TNF-alpha to promote transcription from the IP-10 gene in NIH 3T3 cells. IFN-gamma synergistically enhanced TNF-alpha-induced levels of IP-10 mRNA, whereas levels of JE (MCP-1) or KC (GRO/MGSA) mRNA induced by TNF-alpha were unaffected by IFN-gamma. The cooperation between IFN-gamma and TNF-alpha for induction of IP-10 mRNA was independent of de novo protein synthesis and mediated at least in part by increased transcription. Transient transfection analysis with a 243-bp fragment flanking the transcription start site of the murine IP-10 gene indicated that synergy between the two stimuli was dependent upon occupancy of at least two of three critical regulatory sequence elements: an IFN-stimulated response element (ISRE) and one of two kappa B sites. IFN-gamma and TNF-alpha independently activated nuclear factors capable of specific interaction with the ISRE and kappa B sites, respectively. IFN-gamma induced two ISRE binding complexes, one of which was protein synthesis independent, appeared within 15 min of stimulation, and contained p91 or signal transducer and activator of transcription (STAT) 1. TNF-alpha induced only one ISRE binding activity, which was dependent upon protein synthesis. TNF-alpha also induced kappa B binding activity that was composed of NF-kappa B1 (p50) and RelA (p65) whereas IFN-gamma had no detectable effect on kappa B binding activity. Together these results indicate that the highly synergistic transcriptional activation of the IP-10 gene by IFN-gamma and TNF-alpha involves the cooperation between factors that are independently activated by the two stimuli and that bind to independent sites.