Welting Tim J M, van Venrooij Walther J, Pruijn Ger J M
Department of Biochemistry, Nijmegen Center for Molecular Life Sciences, University of Nijmegen, Nijmegen, The Netherlands.
Nucleic Acids Res. 2004 Apr 19;32(7):2138-46. doi: 10.1093/nar/gkh539. Print 2004.
The eukaryotic ribonuclease for mitochondrial RNA processing (RNase MRP) is mainly located in the nucleoli and belongs to the small nucleolar ribonucleoprotein (snoRNP) particles. RNase MRP is involved in the processing of pre-rRNA and the generation of RNA primers for mitochondrial DNA replication. A closely related snoRNP, which shares protein subunits with RNase MRP and contains a structurally related RNA subunit, is the pre-tRNA processing factor RNase P. Up to now, 10 protein subunits of these complexes have been described, designated hPop1, hPop4, hPop5, Rpp14, Rpp20, Rpp21, Rpp25, Rpp30, Rpp38 and Rpp40. To get more insight into the assembly of the human RNase MRP complex we studied protein-protein and protein-RNA interactions by means of GST pull-down experiments. A total of 19 direct protein-protein and six direct protein-RNA interactions were observed. The analysis of mutant RNase MRP RNAs showed that distinct regions are involved in the direct interaction with protein subunits. The results provide insight into the way the protein and RNA subunits assemble into a ribonucleoprotein particle. Based upon these data a new model for the architecture of the human RNase MRP complex was generated.
用于线粒体RNA加工的真核核糖核酸酶（RNase MRP）主要位于核仁中，属于小核仁核糖核蛋白（snoRNP）颗粒。RNase MRP参与前体rRNA的加工以及线粒体DNA复制所需RNA引物的生成。一种与之密切相关的snoRNP是前体tRNA加工因子RNase P，它与RNase MRP共享蛋白质亚基，并含有一个结构相关的RNA亚基。到目前为止，已经描述了这些复合物的10个蛋白质亚基，分别命名为hPop1、hPop4、hPop5、Rpp14、Rpp20、Rpp21、Rpp25、Rpp30、Rpp38和Rpp40。为了更深入了解人类RNase MRP复合物的组装过程，我们通过GST下拉实验研究了蛋白质-蛋白质和蛋白质-RNA相互作用。共观察到19种直接的蛋白质-蛋白质相互作用和6种直接的蛋白质-RNA相互作用。对突变型RNase MRP RNA的分析表明，不同区域参与了与蛋白质亚基的直接相互作用。这些结果为蛋白质和RNA亚基组装成核糖核蛋白颗粒的方式提供了见解。基于这些数据，构建了人类RNase MRP复合物结构的新模型。
