U3, U8 AND U13 COMPRISE A NEW CLASS OF MAMMALIAN SNRNPS LOCALIZED IN THE CELL NUCLEOLUS
U3, U8 AND U13 COMPRISE A NEW CLASS OF MAMMALIAN SNRNPS LOCALIZED IN THE CELL NUCLEOLUS
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DOI：
10.1002/j.1460-2075.1989.tb08463.x
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发表时间：
1989-10-01
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：
TYC, K;STEITZ, JA
使用抗（U3）RNP自身抗体，我们已经从HeLa细胞中分离和表征了两个额外的小核仁RNA，其丰度低于U3 RNA。这两种RNA都具有三甲基鸟苷帽，通过用抗TMG抗体沉淀来判断，但不被抗Sm或抗La抗体沉淀。此外，这两种RNA都不能被抗Th血清沉淀，抗Th血清识别另一种核仁RNP自身抗原。序列分析显示，其中一个136个核苷酸长的RNA是人类U8同源物;而另一个105个核苷酸长的RNA代表一个新物种，我们将其命名为U13。两种RNA与U3共享两个保守序列（框C和D）。这些框中的一个或两个在结合共同的34 kD抗原蛋白，否则被称为原纤蛋白的作用进行了讨论。HeLa细胞的分级显示，U8和U13，像U3一样，驻留在核仁中。在甘油梯度中，两种RNA与可能代表核糖体前体的较大结构共沉积。我们建议，U3，U8和U13包括一个新的哺乳动物snRNP的子集，其在核糖体生物合成中的作用进行了讨论。
Using anti-(U3)RNP autoantibodies, we have isolated and characterized two additional small nucleolar RNAs from HeLa cells, which are less abundant than U3 RNA. Both RNAs possess a trimethylguanosine cap as judged by precipitation with anti-TMG antibody, but are not precipitated by either anti-Sm or anti-La antibodies. In addition, both RNAs are not precipitable by anti-Th serum, which recognizes another nucleolar RNP autoantigen. Sequence analysis revealed that one of these RNAs, 136 nucleotides long, is the human U8 homolog; while the other, 105 nucleotides long, represents a novel species which we designate U13. Both RNAs share with U3 two conserved sequences (boxes C and D). The role of one or both of these boxes in binding the common 34 kd antigenic protein, otherwise known as fibrillarin, is discussed. Fractionation of HeLa cells revealed that U8 and U13, like U3, reside in the nucleolus. In glycerol gradients both RNAs cosediment with larger structures possibly representing ribosomal precursors. We propose that U3, U8 and U13 comprise a new subset of mammalian snRNPs whose roles in ribosome biogenesis are discussed.