Department of Molecular Microbiology, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, 31096, Israel.
Cell. 2010 Nov 12;143(4):552-63. doi: 10.1016/j.cell.2010.10.033.
Little is known about crosstalk between the eukaryotic transcription and translation machineries that operate in different cell compartments. The yeast proteins Rpb4p and Rpb7p represent one such link as they form a heterodimer that shuttles between the nucleus, where it functions in transcription, and the cytoplasm, where it functions in the major mRNA decay pathways. Here we show that the Rpb4/7 heterodimer interacts physically and functionally with components of the translation initiation factor 3 (eIF3), and is required for efficient translation initiation. Efficient translation in the cytoplasm depends on association of Rpb4/7 with RNA polymerase II (Pol II) in the nucleus, leading to a model in which Pol II remotely controls translation. Hence, like in prokaryotes, the eukaryotic translation is coupled to transcription. We propose that Rpb4/7, through its interactions at each step in the mRNA lifecycle, represents a class of factors, "mRNA coordinators," which integrate the various stages of gene expression into a system.
关于在不同细胞区室中发挥作用的真核转录和翻译机制之间的串扰，人们知之甚少。酵母蛋白 Rpb4p 和 Rpb7p 就是这样的一个联系，因为它们形成一个异二聚体，在核内穿梭，在核内发挥转录功能，在细胞质内发挥主要的 mRNA 降解途径的功能。在这里，我们表明 Rpb4/7 异二聚体与翻译起始因子 3（eIF3）的成分在物理上和功能上相互作用，并且是有效翻译起始所必需的。细胞质中的有效翻译依赖于 Rpb4/7 在核内与 RNA 聚合酶 II（Pol II）的结合，导致 Pol II 远程控制翻译的模型。因此，与原核生物一样，真核翻译与转录偶联。我们提出，Rpb4/7 通过其在 mRNA 生命周期的每个步骤中的相互作用，代表了一类因子，“mRNA 协调因子”，它们将基因表达的各个阶段整合到一个系统中。
