Processing of the intron-encoded U16 and U18 snoRNAs: The conserved C and D boxes control both the processing reaction and the stability of the mature snoRNA
Processing of the intron-encoded U16 and U18 snoRNAs: The conserved C and D boxes control both the processing reaction and the stability of the mature snoRNA
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DOI：
10.1002/j.1460-2075.1996.tb00450.x
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发表时间：
1996-03-01
期刊：
影响因子：
11.4
通讯作者：
Bozzoni, I
中科院分区：
文献类型：
--
作者：
Caffarelli, E;Fatica, A;Bozzoni, I
近年来发现了一类新的核仁小RNA（snoRNA），它编码于蛋白质编码基因的内含子中，起源于其前体分子的加工过程。非洲爪蟾的L1核糖体蛋白（r-蛋白）基因及其人类同源物含有两个snoRNA，U16和U18。已经表明，这些snoRNA通过内切核酸裂解从其内含子前体中切除，并且它们的加工是剪接的替代。snoRNA编码区内部的两个序列已经被鉴定为加工保守盒C和D所必需的。竞争实验表明，这些序列与可结合前mRNA和成熟U16 snoRNA的扩散因子相互作用。原纤蛋白，已知与其他snoRNA的C和D盒上形成的复合物相关联，被发现与成熟U16 RNA及其前体分子相关联。这一事实表明，在前体mRNA上形成的复合物在整个加工步骤中保持与U16结合。我们还表明，C和D盒上形成的复合物是稳定成熟snoRNA所必需的。
A novel class of small nucleolar RNAs (snoRNAs), encoded in introns of protein coding genes and originating from processing of their precursor molecules, has recently been described. The L1 ribosomal protein (r-protein) gene of Xenopus laevis and its human homologue contain two snoRNAs, U16 and U18. It has been shown that these snoRNAs are excised from their intron precursors by endonucleolytic cleavage and that their processing is alternative to splicing, Two sequences, internal to the snoRNA coding region, have been identified as indispensable for processing the conserved boxes C and D. Competition experiments have shown that these sequences interact with diffusible factors which can bind both the pre-mRNA and the mature U16 snoRNA. Fibrillarin, which is known to associate with complexes formed on C and D boxes of other snoRNAs, is found in association with mature U16 RNA, as well as with its precursor molecules. This fact suggests that the complex formed on the pre-mRNA remains bound to U16 throughout all the processing steps. We also show that the complex formed on the C and D boxes is necessary to stabilize mature snoRNA.