Culjkovic Biljana, Topisirovic Ivan, Skrabanek Lucy, Ruiz-Gutierrez Melisa, Borden Katherine L B
Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H4M 1J6, Canada.
J Cell Biol. 2006 Nov 6;175(3):415-26. doi: 10.1083/jcb.200607020. Epub 2006 Oct 30.
This study demonstrates that the eukaryotic translation initiation factor eIF4E is a critical node in an RNA regulon that impacts nearly every stage of cell cycle progression. Specifically, eIF4E coordinately promotes the messenger RNA (mRNA) export of several genes involved in the cell cycle. A common feature of these mRNAs is a structurally conserved, approximately 50-nucleotide element in the 3' untranslated region denoted as an eIF4E sensitivity element. This element is sufficient for localization of capped mRNAs to eIF4E nuclear bodies, formation of eIF4E-specific ribonucleoproteins in the nucleus, and eIF4E-dependent mRNA export. The roles of eIF4E in translation and mRNA export are distinct, as they rely on different mRNA elements. Furthermore, eIF4E-dependent mRNA export is independent of ongoing RNA or protein synthesis. Unlike the NXF1-mediated export of bulk mRNAs, eIF4E-dependent mRNA export is CRM1 dependent. Finally, the growth-suppressive promyelocytic leukemia protein (PML) inhibits this RNA regulon. These data provide novel perspectives into the proliferative and oncogenic properties of eIF4E.
本研究表明,真核生物翻译起始因子eIF4E是一个RNA调控子中的关键节点,该调控子几乎影响细胞周期进程的每个阶段。具体而言,eIF4E协同促进参与细胞周期的多个基因的信使核糖核酸(mRNA)输出。这些mRNA的一个共同特征是在3'非翻译区有一个结构保守的、约50个核苷酸的元件,称为eIF4E敏感元件。该元件足以使加帽mRNA定位于eIF4E核体,在细胞核中形成eIF4E特异性核糖核蛋白,以及进行eIF4E依赖的mRNA输出。eIF4E在翻译和mRNA输出中的作用是不同的,因为它们依赖于不同的mRNA元件。此外,eIF4E依赖的mRNA输出独立于正在进行的RNA或蛋白质合成。与NXF1介导的大量mRNA输出不同,eIF4E依赖的mRNA输出依赖于CRM1。最后,生长抑制性早幼粒细胞白血病蛋白(PML)抑制这个RNA调控子。这些数据为eIF4E的增殖和致癌特性提供了新的视角。