Plant dicistronic tRNA-snoRNA genes:: a new mode of expression of the small nucleolar RNAs processed by RNase Z
Plant dicistronic tRNA-snoRNA genes:: a new mode of expression of the small nucleolar RNAs processed by RNase Z
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DOI：
10.1093/emboj/cdg040
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发表时间：
2003-02-03
期刊：
影响因子：
11.4
通讯作者：
Echeverría, M
中科院分区：
文献类型：
--
作者：
Kruszka, K;Barneche, F;Echeverría, M
指导核糖体 RNA 和其他 RNA 修饰的小核仁 RNA (snoRNA) 显示出不同的基因组织和表达模式，具体取决于真核系统：在动物中，大多数是内含子编码的，在酵母中，许多是单顺反子基因，在植物中，大多数是多顺反子（独立或内含子）基因。在这里，我们报告了一个前所未有的组织：植物双顺反子 tRNA-snoRNA 基因。在拟南芥中，我们鉴定了一个编码 12 个新型盒 C/D snoRNA (snoR43) 的基因家族，该基因家族位于 tRNAGly 基因的下游。我们证实它们可能是从 tRNA 基因启动子转录的，产生双顺反子 tRNA(Gly)-snoR43 前体。使用表达标记的 tRNA-snoR43.1 基因的转基因系，我们表明双顺反子前体被准确地加工成 snoR43.1 和 tRNAGly。此外，我们还发现重组 RNase Z（植物 tRNA 3' 加工酶）可在体外有效裂解双顺反子前体，从 tRNA(Gly) 中释放 snoR43.1。最后，我们描述了水稻中的一个类似案例，涉及与新型 C/D snoRNA 融合表达的 tRNA（Met-e），表明这种 snoRNA 表达模式在遥远的植物物种中也存在。
Small nucleolar RNAs (snoRNAs) guiding modifications of ribosomal RNAs and other RNAs display diverse modes of gene organization and expression depending on the eukaryotic system: in animals most are intron encoded, in yeast many are monocistronic genes and in plants most are polycistronic (independent or intronic) genes. Here we report an unprecedented organization: plant dicistronic tRNA-snoRNA genes. In Arabidopsis thaliana we identified a gene family encoding 12 novel box C/D snoRNAs (snoR43) located just downstream from tRNAGly genes. We confirmed that they are transcribed, probably from the tRNA gene promoter, producing dicistronic tRNA(Gly)-snoR43 precursors. Using transgenic lines expressing a tagged tRNA-snoR43.1 gene we show that the dicistronic precursor is accurately processed to both snoR43.1 and tRNAGly. In addition, we show that a recombinant RNase Z, the plant tRNA 3' processing enzyme, efficiently cleaves the dicistronic precursor in vitro releasing the snoR43.1 from the tRNA(Gly). Finally, we describe a similar case in rice implicating a tRNA(Met-e) expressed in fusion with a novel C/D snoRNA, showing that this mode of snoRNA expression is found in distant plant species.