In vivo identification of nuclear factors interacting with the conserved elements of box C/D small nucleolar RNAs
In vivo identification of nuclear factors interacting with the conserved elements of box C/D small nucleolar RNAs
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DOI：
10.1128/mcb.18.2.1023
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发表时间：
1998-02-01
影响因子：
5.3
通讯作者：
Bozzoni, I
中科院分区：
文献类型：
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作者：
Caffarelli, E;Losito, M;Bozzoni, I
U16小核仁RNA（snoRNA）由非洲爪蟾的L1（IA，根据新的命名法）核糖体蛋白基因的第三内含子编码，并且起源于其所驻留的前体mRNA的加工。U16 snoRNA属于box CID snoRNA家族，已知其成员组装在含有蛋白质纤维蛋白的核糖核蛋白颗粒（snoRNP）中。我们利用U16 snoRNA来表征与盒C/D类其他成员共有的保守元件相互作用的因子。在这项研究中，我们已经分析了在体内组装的U16 snoRNP颗粒在X。的卵母细胞，并确定了与RNA相互作用的蛋白质，通过紫外交联后的标签转移。该分析揭示了40-和68-kDa表观分子大小的两种蛋白质，其需要完整的盒C和D以及保守的5 '，3'-末端茎用于结合。免疫沉淀实验表明，p40蛋白对应于原纤蛋白，表明这种蛋白质与RNA密切相关。我们建议，fibrillarin和p68代表的RNA结合因子共同弓C/D snoRNP和这两种蛋白质是必不可少的snoRNP颗粒的组装和snoRNA的稳定。
The U16 small nucleolar RNA (snoRNA) is encoded by the third intron of the L1 (IA, according to the novel nomenclature) ribosomal protein gene of Xenopus laevis and originates from processing of the pre-mRNA in which it resides. The U16 snoRNA belongs to the box CID snoRNA family, whose members are known to assemble in ribonucleoprotein particles (snoRNPs) containing the protein fibrillarin. We have utilized U16 snoRNA in order to characterize the factors that interact with the conserved elements common to the other members of the box C/D class. In this study, we have analyzed the in vivo assembly of U16 snoRNP particles in X. laevis oocytes and identified the proteins which interact with the RNA by label transfer after UV cross-linking. This analysis revealed two proteins, of 40- and 68-kDa apparent molecular size, which require intact boxes C and D together with the conserved 5',3'-terminal stem for binding. Immunoprecipitation experiments showed that the p40 protein corresponds to fibrillarin, indicating that this protein is intimately associated with the RNA. We propose that fibrillarin and p68 represent the RNA-binding factors common to bow C/D snoRNPs and that both proteins are essential for the assembly of snoRNP particles and the stabilization of the snoRNA.