核糖体RNA(rRNA)在转录和随后的成熟过程中被广泛修饰。三种类型的修改,核糖部分的2'-O-甲基化,假吡啶化,和基础修改,通过snoRNA驱动的机制或独立的酶引入。修饰的核苷酸聚集在功能上重要的位点,包括肽基转移酶中心(PTC)。因此,据推测,修饰的核苷酸在确保核糖体的功能性中起着重要作用。在这项研究中,我们证明了七个25SrRNA修饰,包括四个进化保守的修改,在PTC附近可以同时耗尽而不损失细胞活力。构建了缺乏三个snoRNA基因(snR34,snR52和snR65)和/或表达spb1(D52A/E679K)和nop2(C424A/C478A)的无酶活性变体的酵母突变体。结果表明,PTC中的rRNA修饰共同有助于真核细胞中的有效翻译。25SrRNA中七个修饰核苷酸的缺乏导致细胞生长减少,冷灵敏度,翻译水平下降,和超精确的翻译,正如减少的误解和无稽之谈所表明的那样。修饰m5C2870在不存在其他六个修饰的核苷酸时至关重要。因此,PTC周围rRNA修饰核苷酸的模式对于最佳核糖体翻译活性和翻译保真度至关重要。
Ribosomal RNAs (rRNAs) are extensively modified during the transcription and subsequent maturation. Three types of modifications, 2\'-O-methylation of ribose moiety, pseudouridylation, and base modifications, are introduced either by a snoRNA-driven mechanism or by stand-alone enzymes. Modified nucleotides are clustered at the functionally important sites, including peptidyl transferase center (PTC). Therefore, it has been hypothesised that the modified nucleotides play an important role in ensuring the functionality of the ribosome. In this study, we demonstrate that seven 25S rRNA modifications, including four evolutionarily conserved modifications, in the proximity of PTC can be simultaneously depleted without loss of cell viability. Yeast mutants lacking three snoRNA genes (snR34, snR52, and snR65) and/or expressing enzymatically inactive variants of spb1(D52A/E679K) and nop2(C424A/C478A) were constructed. The results show that rRNA modifications in PTC contribute collectively to efficient translation in eukaryotic cells. The deficiency of seven modified nucleotides in 25S rRNA resulted in reduced cell growth, cold sensitivity, decreased translation levels, and hyperaccurate translation, as indicated by the reduced missense and nonsense suppression. The modification m5C2870 is crucial in the absence of the other six modified nucleotides. Thus, the pattern of rRNA-modified nucleotides around the PTC is essential for optimal ribosomal translational activity and translational fidelity.