Translation fidelity of human ribosomes

信使RNA翻译成功能蛋白质是细胞生命的关键事件。它是由核糖体进行的，核糖体的RNA部分在这种活动中起主要控制作用。核糖体RNA（rRNA）的三个普遍保守的碱基在控制翻译保真度中发挥着重要作用，它们监测着传入的氨酰转移RNA的反密码子和信使RNA的密码子之间的双链体的几何形状。然而，聚集在核糖体功能重要区域的转录后rRNA修饰（主要是2 '-O-核糖甲基化和假尿苷化）似乎有助于优化对翻译保真度的控制。细菌和酵母的翻译准确性已经被深入研究，rRNA修饰的作用也在一定程度上被研究。然而，有一个强烈的需要在哺乳动物细胞中的翻译准确性的调查。我们的目的是研究人类核糖体翻译的准确性，分析两种情况：年轻细胞和衰老（老）细胞。我们将产生能够测量人类细胞中各种类型的翻译错误的报告基因，即有义和无义密码子的错误阅读和阅读框架的移位。这些报告基因将通过逆转录病毒感染引入培养的成纤维细胞中，并将监测年轻细胞和老年细胞中的翻译准确性。我们还将分析年轻细胞和老年细胞核糖体中rRNA的修饰，并研究翻译准确性的变化与rRNA修饰的变化之间是否存在关系。一个长期目标将是探索翻译准确性变化的功能后果，例如错误折叠蛋白质的产生。

Translation of messenger RNAs into functional proteins is a critical event for the cellular life. It is carried out by the ribosomes whose RNA moiety plays the main control in this activity. A major role in the control of translational fidelity is exerted by three universally conserved bases of ribosomal RNA (rRNA) that monitor the geometry of the duplex between the anticodon of the incoming aminoacyl-transfer RNA and the codon of the messenger RNA. However, post-transcriptional rRNA modifications (mostly 2'-O-ribose methylation and pseudouridylation) that cluster in functionally important regions of the ribosome appear to contribute to optimizing the control of translational fidelity. The translation accuracy of bacteria and yeast has been intensively studied and the role of rRNA modifications has also been studied to some extent for these organisms. However, there is a strong need for an investigation of translation accuracy in mammalian cells. Our aim is to investigate the translation accuracy of human ribosomes, analyzing two cases: young cells and senescent (old) cells. We will generate reporters capable of measuring various types of errors in translation in human cells, i.e. misreading of sense and nonsense codons and shifts of the reading frame. Those reporters will be introduced in cultured fibroblasts by retroviral infection and will monitor translation accuracy in young and old cells. The modifications of rRNA in ribosomes from young and old cells will also be analyzed, and we will investigate whether there is a relationship between changes in translation accuracy and changes in rRNA modifications. A long-term goal will be to explore the functional consequences of changes in translational accuracy, such as the production of misfolded proteins.