Assembly factors Rpf2 and Rrs1 recruit 5S rRNA and ribosomal proteins rpL5 and rpL11 into nascent ribosomes
Assembly factors Rpf2 and Rrs1 recruit 5S rRNA and ribosomal proteins rpL5 and rpL11 into nascent ribosomes
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DOI：
10.1101/gad.1569307
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发表时间：
2007-10-15
影响因子：
10.5
通讯作者：
Woolford, John L., Jr.
中科院分区：
文献类型：
--
作者：
Zhang, Jingyu;Harnpicharnchai, Piyanun;Woolford, John L., Jr.
真核生物中核糖体的组装需要超过 170 种蛋白质。然而，与这些蛋白质一起发挥作用的辅因子、它们作用的底物以及组装因子的精确功能（例如，将其他分子招募到前核糖体中或触发前 rRNP 的结构重排）仍然大多未知。在这里，我们研究了两种核糖体蛋白和 5S 核糖体 RNA (rRNA) 招募到新生核糖体中的情况。我们在前核糖体中发现了一个核糖核蛋白邻域，其中包含两个酵母核糖体组装因子 Rpf2 和 Rrs1、两个核糖体蛋白 rpL5 和 rpL11 以及 5S rRNA。这四种蛋白质之间的相互作用已通过体外结合测定得到证实。这些分子组装成含有 35S rRNA 前体 (pre-rRNA) 的 90S 前核糖体颗粒。 Rpf2 和 Rrs1 是将 rpL5、rpL11 和 5S rRNA 招募到前核糖体中所必需的。在这些分子与前 rRNP 不存在关联的情况下，27SB 前 rRNA 的加工被阻断。因此，无效的 66S pre-rRNP 过早地从核仁释放到核质，并且不能输出到细胞质。
More than 170 proteins are necessary for assembly of ribosomes in eukaryotes. However, cofactors that function with each of these proteins, substrates on which they act, and the precise functions of assembly factors -e.g., recruiting other molecules into preribosomes or triggering structural rearrangements of pre-rRNPs -remain mostly unknown. Here we investigated the recruitment of two ribosomal proteins and 5S ribosomal RNA (rRNA) into nascent ribosomes. We identified a ribonucleoprotein neighborhood in preribosomes that contains two yeast ribosome assembly factors, Rpf2 and Rrs1, two ribosomal proteins, rpL5 and rpL11, and 5S rRNA. Interactions between each of these four proteins have been confirmed by binding assays in vitro. These molecules assemble into 90S preribosomal particles containing 35S rRNA precursor (pre-rRNA). Rpf2 and Rrs1 are required for recruiting rpL5, rpL11, and 5S rRNA into preribosomes. In the absence of association of these molecules with pre-rRNPs, processing of 27SB pre-rRNA is blocked. Consequently, the abortive 66S pre-rRNPs are prematurely released from the nucleolus to the nucleoplasm, and cannot be exported to the cytoplasm.