Yeast Pescadillo is required for multiple activities during 60S ribosomal subunit synthesis
Yeast Pescadillo is required for multiple activities during 60S ribosomal subunit synthesis
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DOI：
10.1017/s1355838202020022
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发表时间：
2002-05-01
期刊：
影响因子：
4.5
通讯作者：
Tollervey, D
中科院分区：
文献类型：
--
作者：
Oeffinger, M;Lueng, A;Tollervey, D
Pescadillo蛋白通过发育缺陷被鉴定，并与细胞周期进程有关。在这里，我们报告，人类Pescadillo和它的酵母同系物（Yph 1 p或Nop 7 p）定位于核仁。Nop 7 p的耗尽导致前60 S颗粒的核积累，表明亚基输出中的缺陷，并且它与核糖体蛋白Rp 125 p的标记形式在遗传上相互作用，这与亚基组装中的作用一致。两种前rRNA加工途径产生5.8S rRNA的替代形式，称为5- 8 S（L）和5.8S（S）。在去除Nop 7 p的细胞中，27 SA（3）pre-rRNA积累，而后期加工中间体和成熟的5.8S（S）rRNA被去除。对于5.8S（L）途径观察到较少的消耗。TAP标记的Nop 7 p共沉淀5.8S（L）和5.8S（S）的前体，但不沉淀成熟的rRNA。我们的结论是，Nop 7 p是27 SA（3）pre-rRNA的有效核酸外切加工所必需的，并在60 S亚基组装和转运中具有额外的功能。Nop 7 p是至少三种不同的前60 S粒子的组成部分，我们认为它在这些复合物中的每一种中都具有不同的功能。
The Pescadillo protein was identified via a developmental defect and implicated in cell cycle progression. Here we report that human Pescadillo and its yeast homolog (Yph1p or Nop7p) are localized to the nucleolus. Depletion of Nop7p leads to nuclear accumulation of pre-60S particles, indicating a defect in subunit export, and it interacts genetically with a tagged form of the ribosomal protein Rp125p, consistent with a role in subunit assembly. Two pre-rRNA processing pathways generate alternative forms of the 5.8S rRNA, designated 5-8S(L) and 5.8S(S). In cells depleted for Nop7p, the 27SA(3) pre-rRNA accumulated, whereas later processing intermediates and the mature 5.8S(S) rRNA were depleted. Less depletion was seen for the 5.8S(L) pathway. TAP-tagged Nop7p coprecipitated precursors to both 5.8S(L) and 5.8S(S) but not the mature rRNAs. We conclude that Nop7p is required for efficient exonucleolytic processing of the 27SA(3) pre-rRNA and has additional functions in 60S subunit assembly and transport. Nop7p is a component of at least three different pre-60S particles, and we propose that it carries out distinct functions in each of these complexes.