Heterogeneous nuclear ribonucleoprotein A1 binds to the 3′-untranslated region and mediates potential 5′-3′-end cross talks of mouse hepatitis virus RNA
Heterogeneous nuclear ribonucleoprotein A1 binds to the 3′-untranslated region and mediates potential 5′-3′-end cross talks of mouse hepatitis virus RNA
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DOI：
10.1128/jvi.75.11.5009-5017.2001
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发表时间：
2001-06-01
影响因子：
5.4
通讯作者：
Lai, MMC
中科院分区：
文献类型：
--
作者：
Huang, PY;Lai, MMC
小鼠肝炎病毒（MHV） RNA的3′-非翻译区（3′-UTR）调控病毒RNA的复制和转录。一些宿主细胞蛋白已经被证明与这个调控区域相互作用。通过紫外交联细胞蛋白的免疫沉淀和重组蛋白的体外结合，我们确定了主要的rna结合蛋白种为异质核糖核蛋白A1 （hnRNP A1）。强hnRNP a1结合位点位于MHV RNA 3′端90 ~ 170个核苷酸处，弱hnRNP a1结合位点位于3′端260 ~ 350个核苷酸处。这些结合位点与另一种细胞蛋白聚嘧啶束结合蛋白（PTB）的负链RNA上的位点互补。影响PTB与3'-UTR负链结合的突变也抑制了hnRNP Al与正链的结合，表明这两种蛋白之间可能存在联系。含有突变hnRNP a1结合位点的缺陷干扰RNA降低了RNA转录和复制活性。此外，hnRNP A1和PTB也结合在MHV RNA的5‘端互补链上，在体外共同介导涉及MHV RNA的5’端和3'端片段的RNP复合物的形成。这些研究表明，hnRNP A1-PTB相互作用为MHV RNA中潜在的5‘-3’交叉对话提供了分子机制，这可能对RNA复制和转录很重要。
The 3'-untranslated region (3'-UTR) of mouse hepatitis virus (MHV) RNA regulates the replication of and transcription from the viral RNA. Several host cell proteins have previously been shown to interact with this regulatory region. By immunoprecipitation of UV-cross-linked cellular proteins and in vitro binding of the recombinant protein, we have identified the major RNA-binding protein species as heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1). A strong hnRNP A1-binding site was located 90 to 170 nucleotides from the 3' end of MHV RNA, and a weak binding site was mapped at nucleotides 260 to 350 from the 3' end. These binding sites are complementary to the sites on the negative-strand RNA that bind another cellular protein, polypyrimidine tract-binding protein (PTB). Mutations that affect PTB binding to the negative strand of the 3'-UTR also inhibited hnRNP Al binding on the positive strand, indicating a possible relationship between these two proteins. Defective-interfering RNAs containing a mutated hnRNP A1-binding site have reduced RNA transcription and replication activities. Furthermore, hnRNP A1 and PTB, both of which also bind to the complementary strands at the 5' end of MHV RNA, together mediate the formation of an RNP complex involving the 5'- and 3'-end fragments of MHV RNA in vitro. These studies suggest that hnRNP A1-PTB interactions provide a molecular mechanism for potential 5'-3' cross talks in MHV RNA, which may be important for RNA replication and transcription.