Pelletier J, Kaplan G, Racaniello V R, Sonenberg N
Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
Mol Cell Biol. 1988 Mar;8(3):1103-12. doi: 10.1128/mcb.8.3.1103-1112.1988.
Poliovirus polysomal RNA is naturally uncapped, and as such, its translation must bypass any 5' cap-dependent ribosome recognition event. To elucidate the manner by which poliovirus mRNA is translated, we have determined the translational efficiencies of a series of deletion mutants within the 5' noncoding region of the mRNA. We found striking differences in translatability among the altered mRNAs when assayed in mock-infected and poliovirus-infected HeLa cell extracts. The results identify a functional cis-acting element within the 5' noncoding region of the poliovirus mRNA which enables it to translate in a cap-independent fashion. The major determinant of this element maps between nucleotides 320 and 631 of the 5' end of the poliovirus mRNA. We also show that this region (320 to 631), when fused to a heterologous mRNA, can function in cis to render the mRNA cap independent in translation.
脊髓灰质炎病毒多聚核糖体RNA天然无帽结构，因此，其翻译必须绕过任何依赖5'帽的核糖体识别事件。为阐明脊髓灰质炎病毒mRNA的翻译方式，我们测定了mRNA 5'非编码区内一系列缺失突变体的翻译效率。当在模拟感染和脊髓灰质炎病毒感染的HeLa细胞提取物中进行检测时，我们发现改变后的mRNA在可翻译性上存在显著差异。结果确定了脊髓灰质炎病毒mRNA 5'非编码区内一个功能性顺式作用元件，该元件使其能够以不依赖帽的方式进行翻译。该元件的主要决定因素位于脊髓灰质炎病毒mRNA 5'端核苷酸320至631之间。我们还表明，该区域（320至631）与异源mRNA融合时，可顺式发挥作用，使mRNA在翻译中不依赖帽结构。
