FACTORS RPF2 & RRS1 RECRUIT 5S RRNA & RPL5 & RPL11 INTO NASCENT RIBS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 真核生物核糖体的组装需要170多种蛋白质。然而，与这些蛋白质中的每一个起作用的辅因子，它们作用的底物，以及组装因子的确切功能--例如，将其他分子招募到前乳糖体中或触发前rRNPs的结构重排--大多仍不清楚。在这里，我们研究了两种核糖体蛋白和5S核糖体RNA(RRNA)在新生核糖体中的募集。我们在前糖体中发现了一个核糖核蛋白邻域，它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。体外结合实验证实了这四种蛋白质之间的相互作用。这些分子组装成含有35S rRNA前体(Pre-rRNA)的90年代胸前颗粒。Rpf2和Rrs1是将rpL5、rpL11和5S rRNA招募到前核糖体所必需的。在这些分子没有与前rRNPs结合的情况下，27Sb前rRNA的处理被阻止。因此，流产的66S前rRNPs过早地从核仁释放到核质中，并且不能输出到细胞质中。描述这项工作的手稿已经发表在《基因与发育》杂志上。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 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. A manuscript describing this work has been published in Genes and Development.