Nariai Masanobu, Tanaka Tomohisa, Okada Takafumi, Shirai Chiharu, Horigome Chihiro, Mizuta Keiko
Department of Bioresource Science and Technology, Graduate School of Biosphere Science, Hiroshima University Kagamiyama, Higashi-Hiroshima 739-8528, Japan.
Nucleic Acids Res. 2005 Aug 12;33(14):4553-62. doi: 10.1093/nar/gki772. Print 2005.
Rrs1p, a ribosomal protein L11-binding protein, has an essential role in biogenesis of 60S ribosomal subunits. We obtained conditionally synthetic lethal allele with the rrs1-5 mutation and determined that the mutation is in REX1, which encodes an exonuclease. The highly conserved leucine at 305 was substituted with tryptophan in rex1-1. The rex1-1 allele resulted in 3'-extended 5S rRNA. Polysome analysis revealed that rex1-1 and rrs1-5 caused a synergistic defect in the assembly of 60S ribosomal subunits. In vivo and in vitro binding assays indicate that Rrs1p interacts with the ribosomal protein L5-5S rRNA complex. The rrs1-5 mutation weakens the interaction between Rrs1p with both L5 and L11. These data suggest that the assembly of L5-5S rRNA on 60S ribosomal subunits coordinates with assembly of L11 via Rrs1p.
Rrs1p是一种核糖体蛋白L11结合蛋白，在60S核糖体亚基的生物合成中起关键作用。我们获得了与rrs1 - 5突变相关的条件性合成致死等位基因，并确定该突变位于REX1中，REX1编码一种核酸外切酶。在rex1 - 1中，305位高度保守的亮氨酸被色氨酸取代。rex1 - 1等位基因导致5S rRNA 3'端延长。多核糖体分析表明，rex1 - 1和rrs1 - 5在60S核糖体亚基组装中导致协同缺陷。体内和体外结合试验表明，Rrs1p与核糖体蛋白L5 - 5S rRNA复合物相互作用。rrs1 - 5突变削弱了Rrs1p与L5和L11之间的相互作用。这些数据表明，60S核糖体亚基上L5 - 5S rRNA的组装通过Rrs1p与L11的组装相协调。
