Gillis P, Malter J S
Department of Pathology, Tulane University School of Medicine, New Orleans, Louisiana 70112.
J Biol Chem. 1991 Feb 15;266(5):3172-7.
Selective mRNA degradation is an important control point in the transient expression of a variety of mRNAs coding for growth regulators. A variety of labile mRNAs coding for lymphokines, cytokines, and oncogenes contain within their 3'-untranslated region an AU-rich region shown to destabilize these messages. We recently identified a cytosolic protein, adenosine-uridine binding factor (AUBF), which complexes with four tandem AUUUA reiterations of a synthetic RNA transcript. We now show that AUBF forms RNase T1-resistant band-shifted complexes with a variety of in vitro transcribed mRNAs including granulocyte-macrophage colony-stimulating factor, interferon-gamma, interleukin-3, c-fos, and v-myc. Formation of complexes was specifically inhibited by AUUUA containing RNA, but not by irrelevant RNA. After brief ultraviolet light-induced cross-linking, AUBF.RNA complexes with the exception of c-fos comigrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Mutations within the AUUUA motifs demonstrate that both nucleotide sequence and secondary structure are important in AUBF.AUUUA RNA complex formation. Based upon these data, we suggest AUBF may interact with a variety of labile mRNAs with multiple AUUUA reiterations or single reiterations within an AU-rich 3'-untranslated region.
选择性mRNA降解是多种编码生长调节因子的mRNA瞬时表达中的一个重要控制点。多种编码淋巴因子、细胞因子和癌基因的不稳定mRNA在其3'-非翻译区内含有一个富含AU的区域，该区域可使这些信息不稳定。我们最近鉴定出一种胞质蛋白，腺苷-尿苷结合因子（AUBF），它与合成RNA转录本的四个串联AUUUA重复序列形成复合物。我们现在表明，AUBF与多种体外转录的mRNA形成抗核糖核酸酶T1的带移复合物，包括粒细胞-巨噬细胞集落刺激因子、干扰素-γ、白细胞介素-3、c-fos和v-myc。复合物的形成被含有AUUUA的RNA特异性抑制，但不被无关RNA抑制。经过短暂的紫外线诱导交联后，除c-fos外，AUBF.RNA复合物在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上共迁移。AUUUA基序内的突变表明，核苷酸序列和二级结构在AUBF.AUUUA RNA复合物形成中都很重要。基于这些数据，我们认为AUBF可能与多种在富含AU的3'-非翻译区内有多个AUUUA重复序列或单个重复序列的不稳定mRNA相互作用。
