TcUBP-1, an mRNA destabilizing factor from trypanosomes, homodimerizes and interacts with novel AU-rich element- and poly(A)-binding proteins forming a ribonucleoprotein complex
TcUBP-1, an mRNA destabilizing factor from trypanosomes, homodimerizes and interacts with novel AU-rich element- and poly(A)-binding proteins forming a ribonucleoprotein complex
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DOI：
10.1074/jbc.m209092200
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发表时间：
2002-12-27
影响因子：
4.8
通讯作者：
Frasch, ACC
中科院分区：
文献类型：
--
作者：
D'Orso, I;Frasch, ACC
锥虫是一种广泛感染人类和动物的原生动物寄生虫，它主要通过转录后机制而不是转录起始水平调节蛋白质的表达。我们以前已经确定了一种名为TcUBP-1的克氏锥虫RNA结合蛋白。该蛋白质通过结合SMUG粘蛋白mRNA的W-非翻译区中的富含AU的元件参与体内mRNA去稳定化（D 'Orso，I.，和Frasch，A. C.（2001）J.Biol.Chem.276，34801-34809）。在这项工作中，我们表明，TcUBP-1是一个类似的450 kDa的核糖核蛋白复合物的一部分，多聚（A）结合蛋白和一个新的18 kDa的RNA结合蛋白，命名为TcUBP-2。重组TcUBP-1和TcUBP-2蛋白通过相似的92-氨基酸RNA识别基序以相似的特异性和亲和力识别富含U的RNA。TcUBP可以通过富含甘氨酸的C-末端区域在体外同源和异源二聚化。这种相互作用也在体内检测的核糖核蛋白复合物的免疫共沉淀和使用酵母双杂交试验。所鉴定的poly（A）-结合蛋白显示在体外破坏TcUBP-1的形成，但不破坏TcUBP-2的形成。TcUBP-1配体的可能作用的途径，管理mRNA的稳定性和阶段特异性表达锥虫进行了讨论。
Trypanosomes, protozoan parasites causing worldwide infections in human and animals, mostly regulate protein expression through post-transcriptional mechanisms and not at the transcription initiation level. We have previously identified a Trypanosoma cruzi RNA-binding protein named TcUBP-1. This protein is involved in mRNA destabilization in vivo through binding to AU-rich elements in the W-untranslated region of SMUG mucin mRNAs (D'Orso, I., and Frasch, A. C. (2001) J. Biol. Chem. 276, 34801-34809). In this work we show that TcUBP-1 is part of an similar to450-kDa ribonucleoprotein complex with a poly(A)-binding protein and a novel 18-kDa RNA-binding protein, named TcUBP-2. Recombinant TcUBP-1 and TcUBP-2 proteins recognize U-rich RNAs with similar specificity and affinity through the similar to92-amino acid RNA recognition motif. TcUBPs can homo- and heterodimerize in vitro through the glycine-rich C-terminal region. This interaction was also detected in vivo by co-immunoprecipitation of the ribonucleoprotein complex and using yeast two-hybrid assay. The poly(A)-binding protein identified was shown to disrupt the formation of TcUBP-1, but not TcUBP-2, homodimers in vitro. The possible role of TcUBP-1 ligands in the pathways that govern mRNA-stability and stage-specific expression in trypanosomes is discussed.