U17/snR30 is a ubiquitous snoRNA with two conserved sequence motifs essential for 18S rRNA production
U17/snR30 is a ubiquitous snoRNA with two conserved sequence motifs essential for 18S rRNA production
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DOI：
10.1128/mcb.24.4.1769-1778.2004
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发表时间：
2004-02-01
影响因子：
5.3
通讯作者：
Kiss, T
中科院分区：
文献类型：
--
作者：
Atzorn, V;Fragapane, P;Kiss, T
酿酒酵母snR30是加工18S rRNA所必需的盒型H/ACA小核核RNA （snoRNA）。在这里，我们发现先前表征的人类、爬行动物、两栖动物和鱼类的U17 snoRNAs代表了酵母snR30的脊椎动物同源物。我们也证实了U17/snR30存在于分裂酵母裂糖酵母和单细胞纤毛原生动物嗜热四膜虫中。进化比较发现，U17/snR30 snoRNAs的3'端发夹包含两个高度保守的序列基序，即m1 （AUAUUCCUA）和m2 （AAACCAU）元件。酵母snR30的突变分析表明，m1和m2元素对于35S pre-rRNA的早期裂解至关重要，因此对于成熟的18S rRNA的产生至关重要。m1和m2基序位于内部环结构的相反链上，它们固定地位于U17/snR30 snoRNAs ACA盒上游7个核苷酸处。U17/snR30是第一个在真核生物pre-rRNA的核分解过程中具有进化保守作用的box H/ACA snoRNA。
Saccharomyces cerevisiae snR30 is an essential box H/ACA small nucleolar RNA (snoRNA) required for the processing of 18S rRNA. Here, we show that the previously characterized human, reptilian, amphibian, and fish U17 snoRNAs represent the vertebrate homologues of yeast snR30. We also demonstrate that U17/snR30 is present in the fission yeast Schizosaccharomyces pombe and the unicellular ciliated protozoan Tetrahymena thermophila. Evolutionary comparison revealed that the 3'-terminal hairpins of U17/snR30 snoRNAs contain two highly conserved sequence motifs, the m1 (AUAUUCCUA) and m2 (AAACCAU) elements. Mutation analysis of yeast snR30 demonstrated that the m1 and m2 elements are essential for early cleavages of the 35S pre-rRNA and, consequently, for the production of mature 18S rRNA. The m1 and m2 motifs occupy the opposite strands of an internal loop structure, and they are located invariantly 7 nucleotides upstream from the ACA box of U17/snR30 snoRNAs. U17/snR30 is the first identified box H/ACA snoRNA that possesses an evolutionarily conserved role in the nucleolytic processing of eukaryotic pre-rRNA.