Rrp15p, a novel component of pre-ribosomal particles required for 60S ribosome subunit maturation
Rrp15p, a novel component of pre-ribosomal particles required for 60S ribosome subunit maturation
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DOI：
10.1261/rna.7200205
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发表时间：
2005-04-01
期刊：
影响因子：
4.5
通讯作者：
Fatica, A
中科院分区：
文献类型：
--
作者：
De Marchis, ML;Giorgi, A;Fatica, A
在真核生物中，核糖体生物发生需要 rRNA 初级转录物在前核糖体颗粒中组装并进行加工。参与这一复杂途径的蛋白质因子和前核糖体复合物尚未完全描述。必需的 ORF YPR143W 在酵母中编码一种未表征的蛋白质产物，此处命名为 Rrp15p。即使涉及核仁位置，迄今为止 Rrp15p 的细胞功能尚未确定。为了确定该孤儿基因的可能作用，我们对 Rrp15p 进行了 TAP 标记，并研究了其与已知的前核糖体复合物的分子关联。对表达 TAP 标记的 Rrp15p 的酵母裂解物进行的比较蔗糖梯度沉降分析强烈表明该蛋白质是 60S 前颗粒的组成部分。 Northern 杂交、引物延伸和 TAP 亲和分离复合物的功能蛋白质组学证明，Rrp15p 主要与前 rRNA 和蛋白质相关，这些前 rRNA 和蛋白质先前被定性为早期前 60S 核糖体颗粒的成分。最后，Rrp15p 的消耗抑制了 27S 和 7S pre-rRNA 以及 5.8S 和 25S 成熟 rRNA 的积累。这些结果首次表明 Rrp15p 是参与 60S 亚基早期成熟步骤的新因子。此外，本文报道的含有 Rrp15p 的前核糖体颗粒中蛋白激酶 CK2 的鉴定维持了核糖体合成与细胞周期进程之间的联系。
In eukaryotes ribosome biogenesis required that rRNAs primary transcripts are assembled in pre-ribosomal particles and processed. Protein factors and pre-ribosomal complexes involved in this complex pathway are not completely depicted. The essential ORF YPR143W encodes in yeast for an uncharacterized protein product, named here Rrp15p. Cellular function of Rrp15p has not so far defined even if nucleolar location was referred. With the aim to define the possible role of this orphan gene, we performed TAP-tagging of Rrp15p and investigated its molecular association with known pre-ribosomal complexes. Comparative sucrose gradient sedimentation analyses of yeast lysates expressing the TAP-tagged Rrp15p, strongly indicated that this protein is a component of the pre-60S particles. Northern hybridization, primer extension and functional proteomics on TAP-affinity isolated complexes proved that Rrp15p predominately associated with pre-rRNAs and proteins previously characterized as components of early pre-60S ribosomal particles. Finally, depletion of Rrp15p inhibited the accumulation of 27S and 7S pre-rRNAs and 5.8S and 25S mature rRNA. These results provide the first indication that Rrp15p is a novel factor involved in the early maturation steps of the 60S subunits. Moreover, the identification of the protein kinase CK2 in the Rrp15p-containing pre-ribosomal particles here reported, sustains the link between ribosome synthesis and cell cycle progression.