Jang S K, Kräusslich H G, Nicklin M J, Duke G M, Palmenberg A C, Wimmer E
Department of Microbiology, School of Medicine, State University of New York, Stony Brook 11794-8621.
J Virol. 1988 Aug;62(8):2636-43. doi: 10.1128/JVI.62.8.2636-2643.1988.
Picornavirus RNAs are uncapped messengers and have unusually long 5' nontranslated regions (5'NTRs) which contain many noninitiating AUG triplets. The translational efficiency of different picornavirus RNAs varies between different cell-free extracts and even in the same extract, such as micrococcal nuclease-treated rabbit reticulocyte lysates. The effect of the poliovirus 5'NTR on in vitro translation was compared with that of the 5'NTR of encephalomyocarditis virus by the use of synthetic mRNAs, micrococcal nuclease-treated HeLa cell extracts, and rabbit reticulocyte lysates. Artificial mono- and dicistronic mRNAs synthesized with T7 RNA polymerase were used to investigate whether the 5'NTR of encephalomyocarditis virus RNA contains a potential internal ribosomal entry site. The sequence between nucleotides 260 and 484 in the 5'NTR of encephalomyocarditis RNA was found to play a critical role in the efficient translation in both mono- and dicistronic mRNAs. Our data suggest that an internal ribosomal entry site resides in this region.
小核糖核酸病毒RNA是无帽信使RNA，具有异常长的5'非翻译区（5'NTRs），其中包含许多非起始AUG三联体。不同小核糖核酸病毒RNA的翻译效率在不同的无细胞提取物之间有所不同，甚至在相同的提取物中也是如此，比如经微球菌核酸酶处理的兔网织红细胞裂解物。通过使用合成mRNA、经微球菌核酸酶处理的HeLa细胞提取物和兔网织红细胞裂解物，比较了脊髓灰质炎病毒5'NTR和脑心肌炎病毒5'NTR对体外翻译的影响。用T7 RNA聚合酶合成的人工单顺反子和双顺反子mRNA被用于研究脑心肌炎病毒RNA的5'NTR是否包含一个潜在的内部核糖体进入位点。发现脑心肌炎病毒RNA的5'NTR中核苷酸260至484之间的序列在单顺反子和双顺反子mRNA的有效翻译中起关键作用。我们的数据表明，一个内部核糖体进入位点位于该区域。
