Vitali Patrice, Royo Hélène, Seitz Hervé, Bachellerie Jean-Pierre, Hüttenhofer Alexander, Cavaillé Jérôme
Institute for Molecular Biology, Department of Functional Genomics, University of Innsbruck, Peter-Mayr-Strasse 4b, 6020 Innsbruck, Austria.
Nucleic Acids Res. 2003 Nov 15;31(22):6543-51. doi: 10.1093/nar/gkg849.
Members of the two expanding RNA subclasses termed C/D and H/ACA RNAs guide the 2'-O-methylations and pseudouridylations, respectively, of rRNA and spliceosomal RNAs (snRNAs). Here, we report on the identification of 13 novel human intron-encoded small RNAs (U94-U106) belonging to the two subclasses of modification guides. Seven of them are predicted to direct 2'-O-methylations in rRNA or snRNAs, while the remainder represent novel orphan RNA modification guides. From these, U100, which is exclusively detected in Cajal bodies (CBs), is predicted to direct modification of a U6 snRNA uridine, U(9), which to date has not been found to be pseudouridylated. Hence, within CBs, U100 might function in the folding pathway or other aspects of U6 snRNA metabolism rather than acting as a pseudouridylation guide. U106 C/D snoRNA might also possess an RNA chaperone activity only since its two conserved antisense elements match two rRNA sequences devoid of methylated nucleotides and located remarkably close to each other within the 18S rRNA secondary structure. Finally, we have identified a retrogene for U99 snoRNA located within an intron of the Siat5 gene, supporting the notion that retro-transposition events might have played a substantial role in the mobility and diversification of snoRNA genes during evolution.
被称为C/D和H/ACA RNA的两个不断扩展的RNA亚类的成员，分别指导核糖体RNA（rRNA）和剪接体RNA（snRNA）的2'-O-甲基化和假尿苷酸化。在此，我们报告了13种新的人类内含子编码小RNA（U94-U106）的鉴定结果，它们属于修饰指导的两个亚类。其中7种预计可指导rRNA或snRNA中的2'-O-甲基化，其余的则代表新的孤儿RNA修饰指导分子。其中，仅在卡哈尔体（CBs）中检测到的U100，预计可指导U6 snRNA尿苷U(9)的修饰，而U(9)迄今为止尚未发现有假尿苷酸化现象。因此，在CBs内，U100可能在U6 snRNA代谢的折叠途径或其他方面发挥作用，而不是作为假尿苷酸化指导分子。U106 C/D小核仁RNA（snoRNA）可能也仅具有RNA伴侣活性，因为其两个保守的反义元件与两个没有甲基化核苷酸的rRNA序列匹配，并且在18S rRNA二级结构中彼此非常接近。最后，我们在Siat5基因的一个内含子中鉴定出了U99 snoRNA的一个反转录基因，这支持了反转录事件可能在进化过程中snoRNA基因的移动性和多样性方面发挥了重要作用这一观点。
