TRANSCRIPTIONAL INDUCTION BY DOUBLE-STRANDED-RNA IS MEDIATED BY INTERFERON-STIMULATED RESPONSE ELEMENTS WITHOUT ACTIVATION OF INTERFERON-STIMULATED GENE FACTOR-3
TRANSCRIPTIONAL INDUCTION BY DOUBLE-STRANDED-RNA IS MEDIATED BY INTERFERON-STIMULATED RESPONSE ELEMENTS WITHOUT ACTIVATION OF INTERFERON-STIMULATED GENE FACTOR-3
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DOI：
10.1074/jbc.270.33.19624
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发表时间：
1995-08-18
影响因子：
4.8
通讯作者：
SEN, GC
中科院分区：
文献类型：
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作者：
BANDYOPADHYAY, SK;LEONARD, GT;SEN, GC
由I型干扰素（ifn）诱导的许多基因也可由双链RNA诱导。在本研究中，我们探讨了这一诱导过程的机制。通过删除I型IFN基因的细胞系，我们确定了dsRNA对IFN诱导的561基因的诱导是直接的，而不是由IFN的中间合成介导的。与561 mRNA不同，ifn诱导的6-16 mRNA不受dsRNA的诱导。转染研究表明，这两个基因的核心ifn刺激反应元件（ISREs）之间的序列差异并不是它们被dsRNA诱导的差异的原因。561 ISRE中的一个点突变取消了对ifn - α的反应，也使其对dsRNA无反应，从而表明ISRE是dsRNA信号传导的相关顺式作用元件。在转基因细胞系中，我们评估了不同已知isre结合蛋白和酪氨酸激酶在dsRNA诱导的信号转导中的作用，dsRNA在表达干扰素调节因子1反义RNA的细胞中不能诱导561 mRNA，而在表达相应意义mRNA的细胞中却能强烈诱导561 mRNA， dsRNA也能强烈诱导561 mRNA，但ifn - α不能。在不表达功能性酪氨酸激酶Tyk2或JAK1或ISRE结合蛋白，p48或STATE的突变细胞系中，所有这些都是lfn - α信号传导所必需的。然而，在缺乏功能性STAT1的细胞中，dsRNA对561 mRNA的诱导非常低，而STAT1也是ifn - α信号转导所必需的。在这些细胞中表达转染的STAT1 α蛋白，而不表达STAT1 β蛋白，大大增强了561基因的dsRNA诱导能力。这些研究表明，dsRNA使用的isre介导的主要信号通路需要干扰素调节因子1和STAT1 α。然而，这一途径并不需要ifn - α信号的其他已知细胞质成分。
Many genes induced by type I interferons (IFNs) are also induced by double stranded (ds) RNA. In this study, we investigated the mechanism of this induction process. Using cell lines from which the type I IFN genes have been deleted, we established that induction by dsRNA of the IFN-inducible 561 gene is direct and not mediated by the intermediate synthesis of IFN. Unlike 561 mRNA, the IFN-inducible 6-16 mRNA was induced poorly by dsRNA. Transfection studies demonstrated that the sequence difference between the core IFN-stimulated response elements (ISREs) of these two genes is not responsible for their differential inducibility by dsRNA. A point mutation in the 561 ISRE that abolished its response to IFN-alpha also made it unresponsive to dsRNA, thus demonstrating that the ISRE is the relevant cis acting element for dsRNA signaling. The roles of different known ISRE-binding protein and tyrosine kinases in transducing the signal elicited by dsRNA were evaluated in genetically altered cell lines, dsRNA failed to induce 561 mRNA in cells expressing an antisense RNA for interferon regulatory factor 1, whereas it was induced strongly in cells expressing the corresponding sense mRNA, 561 mRNA was also induced strongly by dsRNA, but not by IFN-alpha, in mutant cell lines that do not express functional tyrosine kinases Tyk2 or JAK1 or ISRE binding protein, p48, or STATE, all of which are required for LFN-alpha signaling. However, in cells devoid of functional STAT1, which is also required for IFN-alpha signaling, the induction of 561 mRNA by dsRNA was very low. Expression of transfected STAT1 alpha protein, but not of STAT1 beta protein, in these cells greatly enhanced the dsRNA inducibility of the 561 gene. These studies indicate that the major ISRE-mediated signaling pathway used by dsRNA requires interferon regulatory factor 1 and STAT1 alpha. This pathway, however, does not require the other known cytoplasmic components used for IFN-alpha signaling.