The NOG1 GTP-binding protein is required for biogenesis of the 60 S ribosomal subunit
The NOG1 GTP-binding protein is required for biogenesis of the 60 S ribosomal subunit
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DOI：
10.1074/jbc.m304198200
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发表时间：
2003-08-22
影响因子：
4.8
通讯作者：
Parsons, M
中科院分区：
文献类型：
--
作者：
Jensen, BC;Wang, Q;Parsons, M
NOG1是一种核仁GTP结合蛋白，广泛存在于从锥虫到人类的真核生物中。在这份报告中，我们证明了NOG1在功能上与核糖体的生物发生有关。在蔗糖密度梯度中，布氏锥虫NOG1与60个S核糖体亚基共沉淀，但不与单体共沉淀。60个S前体RNA与NOG1共沉淀。结合NOG1的核仁定位，这些数据表明NOG1与60 S亚基的前体颗粒有关。通过RNA干扰干扰NOG1的功能，导致60个S颗粒的游离水平急剧下降，并出现了一个不典型的未切割ITS2的rRNA中间体。突变体nog1在野生型背景下的过度表达及其GTP结合基序的缺陷导致了60 S生物发生的适度缺陷和大亚基rRNA加工的相对减少。与突变蛋白相反，NOG1的N端一半包含GTP结合基序，也不是NOG1的C端一半与核糖体前颗粒相关，尽管两者都定位于核仁。
NOG1 is a nucleolar GTP-binding protein present in eukaryotes ranging from trypanosomes to humans. In this report we demonstrate that NOG1 is functionally linked to ribosome biogenesis. In sucrose density gradients Trypanosoma brucei NOG1 co-sediments with 60 S ribosomal subunits but not with monosomes. 60 S precursor RNAs are co-precipitated with NOG1. Together with the nucleolar localization of NOG1, these data indicate that NOG1 is associated with a precursor particle to the 60 S subunit. Disruption of NOG1 function through RNA interference led to a dramatic decrease in the levels of free 60 S particles and the appearance of an atypical rRNA intermediate in which ITS2 was not cleaved. Overexpression of mutant nog1 with a defect in its GTP binding motif on a wild type background caused a modest defect in 60 S biogenesis and a relative decrease in processing of the large subunit rRNAs. In contrast to the mutant protein, neither the N-terminal half of NOG1, which contains the GTP binding motifs, nor the C-terminal half of NOG1 associated with pre-ribosomal particles, although both localized to the nucleolus.