Lebreton Alice, Saveanu Cosmin, Decourty Laurence, Rain Jean-Christophe, Jacquier Alain, Fromont-Racine Micheline
Génétique des Interactions Macromoléculaires, Centre National de la Recherche Scientifique URA2171, Institut Pasteur, 75724 Paris Cedex 15, France.
J Cell Biol. 2006 May 8;173(3):349-60. doi: 10.1083/jcb.200510080. Epub 2006 May 1.
Eukaryotic pre-ribosomes go through cytoplasmic maturation steps before entering translation. The nucleocytoplasmic proteins participating in these late stages of maturation are reimported to the nucleus. In this study, we describe a functional network focused on Rei1/Ybr267w, a strictly cytoplasmic pre-60S factor indirectly involved in nuclear 27S pre-ribosomal RNA processing. In the absence of Rei1, the nuclear import of at least three other pre-60S factors is impaired. The accumulation in the cytoplasm of a small complex formed by the association of Arx1 with a novel factor, Alb1/Yjl122w, inhibits the release of the putative antiassociation factor Tif6 from the premature large ribosomal subunits and its recycling to the nucleus. We propose a model in which Rei1 is a key factor for the coordinated dissociation and recycling of the last pre-60S factors before newly synthesized large ribosomal subunits enter translation.
真核生物前核糖体在进入翻译之前要经历细胞质成熟步骤。参与这些成熟后期阶段的核质蛋白会被重新输入细胞核。在本研究中,我们描述了一个以Rei1/Ybr267w为核心的功能网络,Rei1/Ybr267w是一种严格定位于细胞质的前60S因子,间接参与核内27S前核糖体RNA的加工。在缺乏Rei1的情况下,至少其他三种前60S因子的核输入会受到损害。由Arx1与一种新因子Alb1/Yjl122w结合形成的小复合物在细胞质中的积累,会抑制假定的抗结合因子Tif6从过早形成的大核糖体亚基中释放以及其向细胞核的循环利用。我们提出了一个模型,其中Rei1是新合成的大核糖体亚基进入翻译之前最后一批前60S因子进行协同解离和循环利用的关键因子。