A potential regulatory role for mRNA secondary structures within the prothrombin 3′UTR
A potential regulatory role for mRNA secondary structures within the prothrombin 3′UTR
复制标题
DOI：
10.1016/j.thromres.2010.04.010
复制
发表时间：
2010-08-01
影响因子：
7.5
通讯作者：
Russell, J. Eric
中科院分区：
文献类型：
--
作者：
Liu, Xingge;Jiang, Yong;Russell, J. Eric
凝血酶原mRNA远端3‘非编码区显示出明显的序列异质性，反映了一种不准确的3’-裂解/多聚腺苷化反应。这个相同的区域包含一个单核苷酸多态，它增强了新生凝血酶原转录本的正常转录后处理。这两个观察结果都表明3‘非编码区结构对凝血酶原mRNA的相关生理特性具有重要意义。使用基于HepG2的模型系统，我们绘制了包含凝血酶原3‘UTR的报告mRNAs的一级结构，以及常见的、信息量丰富的3’UTR加工变体的二级结构。随后使用层析方法来评估结构异质性对候选反式作用调节因子结合的影响。我们观察到凝血酶原3‘非编码区在7个或更多的位置组成多聚腺苷，并且可以折叠成至少两个不同的茎环构象。这些替代结构暴露/隔离了hnRNP-I/PTB-1的共识结合位点，hnRNP-I/PTB-1是一种具有转录后调节特性的反式作用因子。HnRNP-I/PTB-1在体外对交替的3‘UTR二级结构表现出不同的亲和力，预示着体内相应的调节作用。这些分析证实了凝血酶原3‘非编码区的结构与其正常功能之间的关键联系，为进一步研究该区域自然发生的基因多态性的分子病理生理学提供了基础。(C)2010爱思唯尔有限公司。保留所有权利。
The distal 3'UTR of prothrombin mRNA exhibits significant sequence heterogeneity reflecting an inexact 3'-cleavage/polyadenylation reaction. This same region encompasses a single-nucleotide polymorphism that enhances the normal post-transcriptional processing of nascent prothrombin transcripts. Both observations indicate the importance of 3'UTR structures to physiologically relevant properties of prothrombin mRNA. Using a HepG2-based model system, we mapped both the primary structures of reporter mRNAs containing the prothrombin 3'UTR, as well as the secondary structures of common, informative 3'UTR processing variants. A chromatographic method was subsequently employed to assess the effects of structural heterogeneities on the binding of candidate trans-acting regulatory factors. We observed that prothrombin 3'UTRs are constitutively polyadenylated at seven or more positions, and can fold into at least two distinct stem-loop conformations. These alternate structures expose/sequester a consensus binding site for hnRNP-I/PTB-1, a trans-acting factor with post-transcriptional regulatory properties. hnRNP-I/PTB-1 exhibits different affinities for the alternate 3'UTR secondary structures in vitro, predicting a corresponding regulatory role in vivo. These analyses demonstrate a critical link between the structure of the prothrombin 3'UTR and its normal function, providing a basis for further investigations into the molecular pathophysiology of naturally occurring polymorphisms within this region. (C) 2010 Elsevier Ltd. All rights reserved.