Nonsense-mediated mRNA decay involves two distinct Upf1-bound complexes
Nonsense-mediated mRNA decay involves two distinct Upf1-bound complexes
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DOI：
10.15252/embj.201899278
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发表时间：
2018-11-02
期刊：
影响因子：
11.4
通讯作者：
Saveanu, Cosmin
中科院分区：
文献类型：
--
作者：
Dehecq, Marine;Decourty, Laurence;Saveanu, Cosmin
无义介导的mRNA降解（NMD）是一种依赖于转录的RNA降解途径，参与许多细胞途径，对端粒的维持和胚胎发育至关重要。核心NMD因子Upf 1、Upf 2和Upf 3从酵母到哺乳动物都是保守的，但缺乏通用的NMD模型。我们使用亲和纯化结合质谱和改进的数据分析方案来表征酵母NMD复合物在酵母中的组成和动力学（112个实验）。出乎意料的是，我们发现了两种与Upf 1相关的不同复合物：Upf 1 -23（Upf 1，Upf 2，Upf 3）和Upf 1-decapping。Upf 1-decapping包含mRNA decapping酶，以及Nmd 4和Ebs 1，这两种蛋白质全面影响NMD，并且对Upf 1 C-末端解旋酶区域介导的RNA降解至关重要。事实上，Nmd 4协会与RNA部分依赖于Upf 1 -23组件和Nmd 4/Ebs 1和哺乳动物Smg 5 -7蛋白之间的相似性表明，NMD通过保守的，连续的Upf 1 -23和Upf 1脱帽复合物。该模型可以扩展到酵母中缺少的步骤，为真核生物中NMD的进一步机制研究服务。
Nonsense-mediated mRNA decay (NMD) is a translation-dependent RNA degradation pathway involved in many cellular pathways and crucial for telomere maintenance and embryo development. Core NMD factors Upf1, Upf2 and Upf3 are conserved from yeast to mammals, but a universal NMD model is lacking. We used affinity purification coupled with mass spectrometry and an improved data analysis protocol to characterize the composition and dynamics of yeast NMD complexes in yeast (112 experiments). Unexpectedly, we identified two distinct complexes associated with Upf1: Upf1-23 (Upf1, Upf2, Upf3) and Upf1-decapping. Upf1-decapping contained the mRNA decapping enzyme, together with Nmd4 and Ebs1, two proteins that globally affected NMD and were critical for RNA degradation mediated by the Upf1 C-terminal helicase region. The fact that Nmd4 association with RNA was partially dependent on Upf1-23 components and the similarity between Nmd4/Ebs1 and mammalian Smg5-7 proteins suggest that NMD operates through conserved, successive Upf1-23 and Upf1-decapping complexes. This model can be extended to accommodate steps that are missing in yeast, to serve for further mechanistic studies of NMD in eukaryotes.