AN INTACT BOX-C SEQUENCE IN THE U3 SNRNA IS REQUIRED FOR BINDING OF FIBRILLARIN, THE PROTEIN COMMON TO THE MAJOR FAMILY OF NUCLEOLAR SNRNPS
AN INTACT BOX-C SEQUENCE IN THE U3 SNRNA IS REQUIRED FOR BINDING OF FIBRILLARIN, THE PROTEIN COMMON TO THE MAJOR FAMILY OF NUCLEOLAR SNRNPS
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DOI：
10.1002/j.1460-2075.1991.tb07807.x
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发表时间：
1991-09-01
期刊：
影响因子：
11.4
通讯作者：
STEITZ, JA
中科院分区：
文献类型：
--
作者：
BASERGA, SJ;YANG, XDW;STEITZ, JA
哺乳动物的U3SnRNP是最近被描述的核仁SNRNP家族的成员之一，该家族还包括U8、U13、U14、X和Y。所有这些SNRNP都能被抗纤维蛋白自身抗体免疫沉淀，这表明34 kDa的纤维蛋白(FB)存在一个共同的结合位点。在这些RNA中存在的两个短核苷酸序列，称为框C和D，是最有可能与纤维蛋白结合的部位。我们建立了纤维蛋白与人U3单链RNA结合的HeLa体外组装系统。在我们的实验中，输入RNA的重建是特异的，因为另外四个具有C和D框的核仁小RNA(U8、U13、X和Y)可被抗纤维蛋白免疫沉淀，而两个缺乏这些序列的RNA(5S和5.8S)则不能。对U3SnRNA的缺失分析表明，纤维蛋白结合需要C框而不是D框。此外，U3Box C中的七个单或双位点特异性突变取消了结合。讨论了C盒-纤维蛋白相互作用在FB单链RNPs生物发生中的作用。
The mammalian U3 snRNP is one member of a recently described family of nucleolar snRNPs which also includes U8, U13, U14, X and Y. All of these snRNPs are immunoprecipitable by anti-fibrillarin autoantibodies, suggesting the existence of a common binding site for the 34 kDa fibrillarin (Fb) protein. Two short nucleotide sequences, called Boxes C and D, present in each of these RNAs are the most likely sites for fibrillarin binding. We have developed a HeLa in vitro assembly system for binding of fibrillarin to human U3 snRNA. Reconstitution of the input RNA is specific in our assay since four of the other nucleolar small RNAs (U8, U13, X and Y) which have Boxes C and D become immunoprecipitable by anti-fibrillarin whereas two RNAs which lack these sequences (5S and 5.8S) do not. Deletion analyses of the U3 snRNA demonstrate that the presence of Box C but not Box D is required for fibrillarin binding. Moreover, seven single or double site-specific mutations in the U3 Box C abolish binding. The role of the Box C-fibrillarin interaction in the biogenesis of the Fb snRNPs is discussed.