Psaridi L, Georgopoulou U, Varaklioti A, Mavromara P
Molecular Virology Laboratory, Hellenic Pasteur Institute, Athens, Greece.
FEBS Lett. 1999 Jun 18;453(1-2):49-53. doi: 10.1016/s0014-5793(99)00662-6.
The 5' untranslated region of hepatitis C virus RNA forms an extensive secondary structure including several hairpin motifs and mediates translation initiation by an internal ribosome entry site-dependent pathway. We report, here, an extensive mutagenesis analysis of a highly conserved tetraloop in the 5' untranslated region of hepatitis C virus, namely hairpin IIIe (295'-GAUA-298'). Our results demonstrate that hairpin IIIe is essential for the internal ribosome entry site function. Moreover, they indicate the importance of the primary structure of this motif because mutations in all four nucleotides of the loop caused a severe loss of internal ribosome entry site activity. These data represent the first experimental evidence for the functional significance of tetraloops in internal ribosome entry site-driven translation of hepatitis C virus.
丙型肝炎病毒RNA的5'非翻译区形成广泛的二级结构，包括几个发夹基序，并通过依赖于内部核糖体进入位点的途径介导翻译起始。我们在此报告对丙型肝炎病毒5'非翻译区中一个高度保守的四环（即发夹IIIe，295'-GAUA-298'）进行的广泛诱变分析。我们的结果表明，发夹IIIe对于内部核糖体进入位点功能至关重要。此外，这些结果表明该基序一级结构的重要性，因为环中所有四个核苷酸的突变都会导致内部核糖体进入位点活性严重丧失。这些数据代表了四环在丙型肝炎病毒内部核糖体进入位点驱动的翻译中的功能意义的首个实验证据。
