Balvay Laurent, Soto Rifo Ricardo, Ricci Emiliano P, Decimo Didier, Ohlmann Théophile
Unité de Virologie Humaine, Ecole Normale Supérieure de Lyon, Lyon F-693643, France.
Biochim Biophys Acta. 2009 Sep-Oct;1789(9-10):542-57. doi: 10.1016/j.bbagrm.2009.07.005. Epub 2009 Jul 24.
Some 20 years ago, the study of picornaviral RNA translation led to the characterization of an alternative mechanism of initiation by direct ribosome binding to the 5' UTR. By using a bicistronic vector, it was shown that the 5' UTR of the poliovirus (PV) or the Encephalomyelitis virus (EMCV) had the ability to bind the 43S preinitiation complex in a 5' and cap-independent manner. This is rendered possible by an RNA domain called IRES for Internal Ribosome Entry Site which enables efficient translation of an mRNA lacking a 5' cap structure. IRES elements have now been found in many different viral families where they often confer a selective advantage to allow ribosome recruitment under conditions where cap-dependent protein synthesis is severely repressed. In this review, we compare and contrast the structure and function of IRESes that are found within 4 distinct family of RNA positive stranded viruses which are the (i) Picornaviruses; (ii) Flaviviruses; (iii) Dicistroviruses; and (iv) Lentiviruses.
大约20年前，对小核糖核酸病毒RNA翻译的研究导致了一种通过核糖体直接结合到5'非翻译区（UTR）的替代起始机制的表征。通过使用双顺反子载体，研究表明脊髓灰质炎病毒（PV）或脑脊髓炎病毒（EMCV）的5'UTR能够以5'和不依赖帽结构的方式结合43S起始前复合物。这是通过一种称为内部核糖体进入位点（IRES）的RNA结构域实现的，该结构域能够使缺乏5'帽结构的mRNA进行高效翻译。现在已经在许多不同的病毒家族中发现了IRES元件，在帽依赖性蛋白质合成受到严重抑制的条件下，它们通常赋予一种选择性优势以允许核糖体募集。在这篇综述中，我们比较并对比了在4个不同的正链RNA病毒家族中发现的IRES的结构和功能，它们分别是：（i）小核糖核酸病毒；（ii）黄病毒；（iii）双顺反子病毒；以及（iv）慢病毒。
