Miyoshi Keita, Tsujii Rota, Yoshida Hideji, Maki Yasushi, Wada Akira, Matsui Yasushi, Toh-E Akio, Mizuta Keiko
Department of Biological Sciences, Graduate School of Biosphere Sciences, Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8528, Japan.
J Biol Chem. 2002 May 24;277(21):18334-9. doi: 10.1074/jbc.M201667200. Epub 2002 Mar 13.
A secretory defect leads to transcriptional repression of both ribosomal protein and rRNA genes in yeast. To elucidate the mechanism of the signaling, we previously isolated rrs mutants that were unable to respond to a secretory defect, and we cloned RRS1 encoding a nuclear protein that was required for ribosome biogenesis (Tsuno, A., Miyoshi, K., Tsujii, R., Miyakawa, T., and Mizuta, K. (2000) Mol. Cell. Biol. 20, 2066-2074). We identified duplicated genes encoding ribosomal protein L11, RPL11B as a wild-type allele complementing the rrs2 mutation, and RPL11A in two-hybrid screening using RRS1 as bait. Rpl11p was copurified with Rrs1p in immunoprecipitation analysis. Ultracentrifugation analysis revealed that Rrs1p associated fairly tightly with 60 S preribosomal subunits. These results suggest that signaling in response to a secretory defect requires the normal assembly of 60 S ribosomal subunits including Rrs1p and Rpl11p.
分泌缺陷会导致酵母中核糖体蛋白基因和rRNA基因的转录抑制。为阐明这种信号传导机制，我们之前分离出了无法对分泌缺陷作出反应的rrs突变体，并克隆了RRS1，它编码一种核糖体生物合成所需的核蛋白（津野，A.，三好，K.，辻井，R.，宫川，T.，水田，K.（2000年）《分子与细胞生物学》20，2066 - 2074）。我们鉴定出编码核糖体蛋白L11的重复基因，RPL11B作为互补rrs2突变的野生型等位基因，以及在以RRS1为诱饵的双杂交筛选中发现的RPL11A。在免疫沉淀分析中，Rpl11p与Rrs1p共同纯化。超速离心分析表明，Rrs1p与60S核糖体亚基前体紧密结合。这些结果表明，对分泌缺陷作出反应的信号传导需要包括Rrs1p和Rpl11p在内的60S核糖体亚基的正常组装。
