RNA病毒翻译调控元件—内部核糖体进入位点(IRES)

真核生物大多数蛋白质合成采用了依赖帽子结构的翻译起始方式.但一组缺乏帽子构的RNA病毒的蛋白质合成起始是依赖其5′端非翻译区（untranslated region，UTR）翻译调控的顺式作用元件——内部核糖体进入位点（internal ribosome entry site, IRES）.它 们能够在一些反式作用因子的辅助下,招募核糖体小亚基到病毒mRNA的翻译起始位点.前，依赖IRES元件翻译起始的RNA病毒在哺乳动物，无脊椎动物及植物中均有发现.因此,对RNA病毒IRES元件的深入研究,不仅有助于阐明相关疾病的发生机理，而且为工业应用和疾病治疗提供借鉴意义.本文对RNA病毒IRES元件发现、分类、结构与功能等作了综述.

IRES: Translation Element of RNA Viruses

Initiation translation of most eukaryotic mRNAs occurs by cap-dependent translation. However, a group of positive sense RNA viruses lacking cap structures can initiate the translation by a cis-element in the 5′untranslated region——internal ribosome entry site (IRES). They can recruit ribosome subunits to the start site of viral mRNA with the aid of certain trans-acting factors. To date，RNA viruses of IRES-dependent translation initiation are discovered in the mammals, invertebrates and plants. IRES elements are grouped in four classes based on the different structure and function. The further study of IRES elements in the RNA viruses will not o nly help the understanding viral pathogenesis, but also provide the guidance for the industrial application and disease therapy. The review focuses on the discovery, classes, structure and function of IRES elements,respectively.