Laboratory for Cancer Medicine, Centre for Medical Research, Western Australian Institute for Medical Research, Perth, WA, 6000, Australia.
J Biochem. 2012 Apr;151(4):423-37. doi: 10.1093/jb/mvs010. Epub 2012 Feb 25.
The stability of RNAs bearing AU-rich elements in their 3'-UTRs, and thus the level of expression of their protein products, is regulated by interactions with cytoplasmic RNA-binding proteins. Binding by HuR generally leads to mRNA stabilization and increased protein production, whereas binding by AUF1 isoforms generally lead to rapid degradation of the mRNA and reduced protein production. The exact nature of the interplay between these and other RNA-binding proteins remains unclear, although recent studies have shown close interactions between them and even suggested competition between the two for binding to their cognate recognition sequences. Other recent reports have suggested that the sequences recognized by the two proteins are different. We therefore performed a detailed in vitro analysis of the binding site(s) for HuR and AUF1 present in androgen receptor mRNA to define their exact target sequences, and show that the same sequence is contacted by both proteins. Furthermore, we analysed a proposed HuR target within the 3'-UTR of MTA1 mRNA, and show that the contacted bases lie outside of the postulated motif and are a better match to a classical ARE than the postulated motif. The defining features of these HuR binding sites are their U-richness and single strandedness.
在其 3'-UTR 中带有富含 AU 元件的 RNA 的稳定性，以及其蛋白质产物的表达水平，受到与细胞质 RNA 结合蛋白相互作用的调节。HuR 的结合通常导致 mRNA 稳定性增加和蛋白质产量增加，而 AUF1 同工型的结合通常导致 mRNA 迅速降解和蛋白质产量降低。这些和其他 RNA 结合蛋白之间相互作用的确切性质尚不清楚，尽管最近的研究表明它们之间存在密切相互作用，甚至表明这两种蛋白之间存在竞争以结合其同源识别序列。其他最近的报告表明，这两种蛋白识别的序列不同。因此，我们对雄激素受体 mRNA 中存在的 HuR 和 AUF1 的结合位点进行了详细的体外分析，以确定其确切的靶序列，并表明这两种蛋白都与相同的序列结合。此外，我们分析了 MTA1 mRNA 3'-UTR 中提出的 HuR 靶标，并表明所接触的碱基位于假定的基序之外，与经典的 ARE 更匹配，而不是假定的基序。这些 HuR 结合位点的特征是富含 U 和单链。
