Post-transcriptional regulation of RNase-L expression is mediated by the 3′-untranslated region of its mRNA
Post-transcriptional regulation of RNase-L expression is mediated by the 3′-untranslated region of its mRNA
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DOI：
10.1074/jbc.m607939200
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发表时间：
2007-03-16
影响因子：
4.8
通讯作者：
Hassel, Bret A.
中科院分区：
文献类型：
--
作者：
Li, Xiao-Ling;Andersen, Jesper B.;Hassel, Bret A.
RNase-L介导关键的细胞功能，包括抗病毒、促凋亡和肿瘤抑制活性；因此，它的表达必须受到严格管制。关于RNASEL表达的调控知之甚少；因此，我们研究了其mRNA中保守的3'-非翻译区（3'-UTR）的潜在调节作用。3′-UTR介导了RNase-L mRNA和嵌合β -珠蛋白-3′-UTR报告基因稳定性的显著降低。富au元素（AREs）是调节mRNA稳定性的顺式调控区域。在rnase - l3 '-UTR中鉴定出8个AREs，缺失分析鉴定出与不同AREs相关的正调控区和负调控区。特别是AREs 7和8具有较强的正向调节功能。HuR是一种are结合蛋白，可以稳定含有are的mrna，并且在包含AREs 7和8的区域中确定了一个预测的HuR结合位点。HuR和RNase-L的共转染增强了RNase-L的表达和mRNA的稳定性，这种方式依赖于这个3'-UTR区域。免疫沉淀表明，在完整细胞中，RNase-L mRNA与含有HuR的复合物相关联。细胞应激或成肌细胞分化过程中内源性HuR的激活可增加RNase-L的表达，表明RNase-L mRNA是HuR的生理靶标。RNase-L的hr依赖性调控增强了其抗病毒活性，证明了该调控的功能意义。这些发现确定了由其3'-UTR介导的RNase-L调控的新机制。
RNase-L mediates critical cellular functions including antiviral, pro-apoptotic, and tumor suppressive activities; accordingly, its expression must be tightly regulated. Little is known about the control of RNASEL expression; therefore, we examined the potential regulatory role of a conserved 3'-untranslated region (3'-UTR) in its mRNA. The 3'-UTR mediated a potent decrease in the stability of RNase-L mRNA, and of a chimeric beta-globin-3'-UTR reporter mRNA. AU-rich elements (AREs) are cis-acting regulatory regions that modulate mRNA stability. Eight AREs were identified in the RNase-L 3'-UTR, and deletion analysis identified positive and negative regulatory regions associated with distinct AREs. In particular, AREs 7 and 8 served a strong positive regulatory function. HuR is an ARE-binding protein that stabilizes ARE-containing mRNAs, and a predicted HuR binding site was identified in the region comprising AREs 7 and 8. Co-transfection of HuR and RNase-L enhanced RNase-L expression and mRNA stability in a manner that was dependent on this 3'-UTR region. Immunoprecipitation demonstrated that RNase-L mRNA associates with a HuR containing complex in intact cells. Activation of endogenous HuR by cell stress, or during myoblast differentiation, increased RNase-L expression, suggesting that RNase-L mRNA is a physiologic target for HuR. HuR-dependent regulation of RNase-L enhanced its antiviral activity demonstrating the functional significance of this regulation. These findings identify a novel mechanism of RNase-L regulation mediated by its 3'-UTR.