Intronic snoRNA biosynthesis in Saccharomyces cerevisiae depends on the lariat-debranching enzyme:: Intron length effects and activity of a precursor snoRNA
Intronic snoRNA biosynthesis in Saccharomyces cerevisiae depends on the lariat-debranching enzyme:: Intron length effects and activity of a precursor snoRNA
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DOI：
10.1017/s1355838298980785
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发表时间：
1998-09-01
期刊：
影响因子：
4.5
通讯作者：
Boeke, JD
中科院分区：
文献类型：
--
作者：
Ooi, SL;Samarsky, DA;Boeke, JD
真核生物的小核仁RNA（snoRNA）参与前体rRNA的加工和rRNA核苷酸的修饰。一些snoRNA来源于单顺反子或多顺反子转录单位，而另一些则编码于蛋白质基因的内含子中。本研究解决的作用RNA lariat-debranching酶（Dbr 1 p）的内含子snoRNA的合成和功能的酵母酿酒酵母。内含子snoRNA的产生取决于Dbr 1 p。成熟的内含子snoRNA的积累减少了dbr 1突变体，相反，内含子snoRNA被“困”在宿主内含子lariats。有趣的是，内含子snoRNA在dbr 1细胞中以lariats形式积累的程度在不同的内含子snoRNA之间存在差异。在较短的内含子内编码的内含子snoRNA，如U24和snR 38，比在较长的内含子内编码的那些积累更多的未加工的lactinase前体，例如，U18和snR 39。用模型内含子：U24 snoRNA构建体进行的实验证实了这种相关性。这些结果支持剪接依赖性核酸外切酶途径的生物合成的内含子snoRNA。令人好奇的是，在一个lactone中的U24可能在指导核糖体RNA的甲基化中起作用。
The eukaryotic small nucleolar RNAs (snoRNAs) are involved in processing of pre-rRNA and modification of rRNA nucleotides. Some snoRNAs are derived from mono- or polycistronic transcription units, whereas others are encoded in introns of protein genes. The present study addresses the role of the RNA lariat-debranching enzyme (Dbr1p) in the synthesis and function of intronic snoRNAs in the yeast Saccharomyces cerevisiae. Intronic snoRNA production was determined to depend on Dbr1p. Accumulation of mature intronic snoRNAs is reduced in a dbr1 mutant; instead, intronic snoRNAs are "trapped" within host intron lariats. Interestingly, the extent of intronic snoRNA accumulation in the form of lariats in dbr1 cells varied among different intronic snoRNAs. Intronic snoRNAs encoded within shorter introns, such as U24 and snR38, accumulate more unprocessed lariat precursors than those encoded within longer introns, e.g., U18 and snR39. This correlation was corroborated by experiments conducted with model intron:U24 snoRNA constructs. These results support a splicing-dependent exonucleolytic pathway for the biosynthesis of intronic snoRNAs. Curiously, U24 in a lariat may be functional in directing methylation of ribosomal RNA.