Saito Yuichiro, Takeda Jun, Adachi Kousuke, Nobe Yuko, Kobayashi Junya, Hirota Kouji, Oliveira Douglas V, Taoka Masato, Isobe Toshiaki
Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo, Japan.
Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Tokyo, Japan.
PLoS One. 2014 Nov 17;9(11):e112488. doi: 10.1371/journal.pone.0112488. eCollection 2014.
Ribonuclease mitochondrial RNA processing (RNase MRP) is a multifunctional ribonucleoprotein (RNP) complex that is involved in the maturation of various types of RNA including ribosomal RNA. RNase MRP consists of a potential catalytic RNA and several protein components, all of which are required for cell viability. We show here that the temperature-sensitive mutant of rmp1, the gene for a unique protein component of RNase MRP, accumulates the dimeric tRNA precursor, pre-tRNA(Ser-Met). To examine whether RNase MRP mediates tRNA maturation, we purified the RNase MRP holoenzyme from the fission yeast Schizosaccharomyces pombe and found that the enzyme directly and selectively cleaves pre-tRNA(Ser-Met), suggesting that RNase MRP participates in the maturation of specific tRNA in vivo. In addition, mass spectrometry-based ribonucleoproteomic analysis demonstrated that this RNase MRP consists of one RNA molecule and 11 protein components, including a previously unknown component Rpl701. Notably, limited nucleolysis of RNase MRP generated an active catalytic core consisting of partial mrp1 RNA fragments, which constitute "Domain 1" in the secondary structure of RNase MRP, and 8 proteins. Thus, the present study provides new insight into the structure and function of RNase MRP.
核糖核酸酶线粒体RNA加工（RNase MRP）是一种多功能核糖核蛋白（RNP）复合物，参与包括核糖体RNA在内的各种类型RNA的成熟过程。RNase MRP由一种潜在的催化RNA和几个蛋白质组分组成，所有这些对于细胞活力都是必需的。我们在此表明，rmp1（RNase MRP独特蛋白质组分的基因）的温度敏感突变体积累了二聚体tRNA前体，即前体tRNA（Ser-Met）。为了研究RNase MRP是否介导tRNA成熟，我们从裂殖酵母粟酒裂殖酵母中纯化了RNase MRP全酶，发现该酶直接且选择性地切割前体tRNA（Ser-Met），这表明RNase MRP在体内参与特定tRNA的成熟。此外，基于质谱的核糖核蛋白质组分析表明，这种RNase MRP由一个RNA分子和11个蛋白质组分组成，包括一个先前未知的组分Rpl701。值得注意的是，RNase MRP的有限核酸酶解产生了一个活性催化核心，该核心由部分mrp1 RNA片段（在RNase MRP二级结构中构成“结构域1”）和8种蛋白质组成。因此，本研究为RNase MRP的结构和功能提供了新的见解。
