Ski7p G protein interacts with the exosome and the Ski complex for 3′-to-5′ mRNA decay in yeast
Ski7p G protein interacts with the exosome and the Ski complex for 3′-to-5′ mRNA decay in yeast
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DOI：
10.1093/emboj/20.17.4684
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发表时间：
2001-09-03
期刊：
影响因子：
11.4
通讯作者：
Katada, T
中科院分区：
文献类型：
--
作者：
Araki, Y;Takahashi, S;Katada, T
在酵母中已经表征了两种细胞质mRNA衰减途径，并且两者都是通过缩短3 '-poly（A）尾来启动的。在主要的5 '-至-3'衰变途径中，去腺苷化触发5 '-帽的去除，使转录物体暴露于5'-至-3 '降解。另一种3 '-至-5'衰变途径也遵循去腺苷化，并且需要两种多复合物：含有各种3 '-外切核酸酶的外泌体和由RNA解旋酶Ski 2 p、Ski 3 p和Ski 8 p组成的Ski复合物。此外，具有N-末端结构域和C-末端延伸因子Ia样GTP结合结构域的Ski 7 p参与3 '至5'衰变。然而，外泌体和Ski复合物之间的物理相互作用以及Ski 7 p的功能仍然未知。在这里，我们报告说，N结构域的Ski 7 p是必要的，并足以为3 '到5'衰变。此外，外泌体和Ski复合物与Ski 7 p N结构域的不同区域相互作用，并且这两种相互作用都是3 '至5'衰变所需的。因此，Ski 7 p G蛋白似乎在3 '至5' mRNA衰变途径中起两个多复合物之间的信号偶联因子的作用。
Two cytoplasmic mRNA-decay pathways have been characterized in yeast, and both are initiated by shortening of the 3'-poly(A) tail. In the major 5'-to-3' decay pathway, the deadenylation triggers removal of the 5'-cap, exposing the transcript body for 5'-to-3' degradation. An alternative 3'-to-5' decay pathway also follows the deadenylation and requires two multi-complexes: the exosome containing various 3'-exonucleases and the Ski complex consisting of the RNA helicase Ski2p, Ski3p and Ski8p. In addition, Ski7p, which has an N-terminal domain and a C-terminal elongation factor la-like GTP-binding domain, is involved in the 3'-to-5' decay. However, physical interaction between the exosome and the Ski complex, together with the function of Ski7p, has remained unknown. Here we report that the N domain of Ski7p is required and sufficient for the 3'-to-5' decay. Furthermore, the exosome and the Ski complex interact with the different regions of Ski7p N domain, and both interactions are required for the 3'-to-5' decay. Thus, Ski7p G protein appears to function as a signal-coupling factor between the two multi-complexes operating in the 3'-to-5' mRNA-decay pathway.