Deadenylation of interferon-β mRNA is mediated by both the AU-rich element in the 3′-untranslated region and an instability sequence in the coding region
Deadenylation of interferon-β mRNA is mediated by both the AU-rich element in the 3′-untranslated region and an instability sequence in the coding region
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DOI：
10.1046/j.1432-1033.2003.03530.x
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发表时间：
2003-04-01
期刊：
影响因子：
--
通讯作者：
Kruys, V
中科院分区：
文献类型：
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作者：
Pasté, M;Huez, G;Kruys, V
成纤维细胞和内皮细胞的病毒感染导致干扰素-β (IFN-β) 的瞬时合成。感染后 IFN-β 合成的下调是由于 IFN-β 基因的转录抑制和 mRNA 的快速降解造成的。与许多细胞因子 mRNA 一样，IFN-β mRNA 在其 3'-非翻译区 (UTR) 中含有富含 AU 的元件 (ARE)。已知 ARE 可介导 mRNA 脱腺苷化和不稳定。根据 ARE 的类别，去腺苷化被证明是通过同步或异步机制发生的。在这项研究中，我们分析了 IFN-β 合成自然条件下（例如病毒感染后）的 IFN-β mRNA 去腺苷化。我们表明，人 IFN-β mRNA 遵循包含 II 类 ARE 的 mRNA 典型的异步去腺苷酸化途径。 IFN-β 天然转录物的缺失分析表明，poly(A) 缩短可以由 ARE 介导，也可以由位于编码区的 32 个核苷酸序列介导，该序列先前被鉴定为不稳定决定因素。事实上，这些元件能够独立发挥作用，因为必须去除它们才能消除 mRNA 去腺苷化。我们的数据还表明去腺苷化的发生独立于 mRNA 翻译。此外，我们表明，IFN-β mRNA 的去腺苷化不受病毒感染的控制，因为源自组成型表达基因盒的 IFN-β mRNA 在没有病毒感染的情况下被去腺苷化。最后，未鉴定的核事件似乎是 IFN-β mRNA 去腺苷化的先决条件，因为直接引入细胞质的 IFN-β mRNA 不会发生去腺苷化。总之，我们的研究表明，IFN-β mRNA 聚腺苷酸缩短受到两个顺式作用元件的控制，这些元件募集去腺苷酸化机制，其活性独立于翻译和病毒感染，但可能需要核事件。
Viral infection of fibroblastic and endothelial cells leads to the transient synthesis of interferon-beta (IFN-beta). The down-regulation of IFN-beta synthesis after infection results both from transcriptional repression of the IFN-beta gene and rapid degradation of mRNA. As with many cytokine mRNAs, IFN-beta mRNA contains an AU-rich element (ARE) in its 3'-untranslated region (UTR). AREs are known to mediate mRNA deadenylation and destabilization. Depending on the class of ARE, deadenylation was shown to occur through synchronous or asynchronous mechanisms. In this study, we analysed IFN-beta mRNA deadenylation in natural conditions of IFN-beta synthesis, e.g., after viral infection. We show that human IFN-beta mRNA follows an asynchronous deadenylation pathway typical of a mRNA containing a class II ARE. A deletion analysis of the IFN-beta natural transcript demonstrates that poly(A) shortening can be mediated by the ARE but also by a 32 nucleotide-sequence located in the coding region, that was identified previously as an instability determinant. In fact, these elements are able to act independently as both of them have to be removed to abrogate mRNA deadenylation. Our data also indicate that deadenylation occurs independently of mRNA translation. Moreover, we show that deadenylation of IFN-beta mRNA is not under the control of viral infection as IFN-beta mRNA derived from a constitutively expressed gene cassette is deadenylated in absence of viral infection. Finally, an unidentified nuclear event appears to be a prerequisite for IFN-beta mRNA deadenylation as IFN-beta mRNA introduced directly into the cytoplasm does not undergo deadenylation. In conclusion, our study demonstrates that IFN-beta mRNA poly(A) shortening is under the control of two cis -acting elements recruiting a deadenylating machinery whose activity is independent of translation and viral infection but might require a nuclear event.