A cis-element in the 3′-untranslated region of IκB-ζ mRNA governs its stimulus-specific expression
A cis-element in the 3′-untranslated region of IκB-ζ mRNA governs its stimulus-specific expression
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DOI：
10.1016/j.bbrc.2007.03.044
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发表时间：
2007-05
影响因子：
3.1
通讯作者：
Satoshi Watanabe;K. Takeshige;T. Muta
中科院分区：
文献类型：
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作者：
Satoshi Watanabe;K. Takeshige;T. Muta
IκB-ζ是炎症反应中必不可少的转录调节因子，可通过刺激toll样受体和白细胞介素(IL)-1β的微生物物质诱导，但不受肿瘤坏死因子(TNF)-α通过特异性mRNA稳定诱导。在这里，我们试图在IκB-ζ mRNA中确定一个具有特异性诱导作用的顺式元件。为了评估各种片段在转录后调控中的活性，我们构建了独特的报告质粒，其中一个片段插入由SV40早期增强子/启动子转录的不稳定荧光素酶cDNA的下游。在NIH3T3细胞中，含有IκB-ζ mRNA的报告质粒在脂多糖或IL-1β刺激后荧光素酶活性升高，但TNF-α没有，表明刺激特异性。我们发现在3 ' -未翻译区有一个165个核苷酸的片段赋予了特异性诱导。通过转染全长IκB-ζ mRNA，观察到刺激特异性诱导IκB-ζ，但未转染无片段的mRNA。因此，该序列对于通过转录后调控机制刺激特异性诱导IκB-ζ至关重要。
IκB-ζ, an essential transcriptional regulator in inflammatory reactions, is induced by microbial substances that stimulate Toll-like receptors and interleukin (IL)-1β but not by tumor necrosis factor (TNF)-α, via specific mRNA stabilization. Here, we attempted to identify a cis-element in IκB-ζ mRNA that confers the specific induction. To evaluate the activities of various fragments in the post-transcriptional regulation, we constructed unique reporter plasmids, in which a fragment was inserted downstream of a destabilized luciferase cDNA transcribed by the SV40 early enhancer/promoter. In NIH3T3 cells, a reporter plasmid harboring IκB-ζ mRNA exhibited elevated luciferase activity following stimulation with lipopolysaccharide or IL-1β, but not TNF-α, indicating the stimulus-specificity. We found that a 165-nucleotide fragment in the 3′-untranslated region conferred the specific induction. Stimulus-specific induction of IκB-ζ was observed by transfection of full-length IκB-ζ mRNA, but not of a mRNA without the fragment. Thus, this sequence is essential for the stimulus-specific induction of IκB-ζ via a post-transcriptional regulatory mechanism.