Inter-kingdom conservation of mechanism of nonsense-mediated mRNA decay
Inter-kingdom conservation of mechanism of nonsense-mediated mRNA decay
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DOI：
10.1038/emboj.2008.88
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发表时间：
2008-06-04
期刊：
影响因子：
11.4
通讯作者：
Silhavy, Daniel
中科院分区：
文献类型：
--
作者：
Kerenyi, Zoltan;Merai, Zsuzsanna;Silhavy, Daniel
无义介导的mRNA衰变（NMD）是降解含有提前终止密码子的mRNA的质量控制系统。虽然NMD在酵母和哺乳动物中得到了很好的表征，但对植物NMD的了解甚少。我们进行了植物NMD途径的功能解剖。使用的方法，允许快速识别植物NMD的反式因子，我们证明了两种植物NMD途径共存，一个消除长30 UTR的mRNA，而一个不同的途径降解的mRNA窝藏30 UTR定位内含子。我们发现，UPF 1，UPF 2和SMG-7参与两种植物NMD途径，而Mago和Y14只需要基于内含子的NMD。基于长30 UTR的植物NMD的分子机制类似于酵母NMD，而基于内含子的NMD类似于哺乳动物NMD，表明这两种途径在进化上是保守的。有趣的是，SMG-7 NMD组分被NMD靶向，表明植物NMD是自动调节的。我们建议，一个复杂的，自动调节的NMD机制在干真核生物中运作，尽管在不同的谱系中被简化的机制方面，反馈调节保留在所有王国。
Nonsense-mediated mRNA decay (NMD) is a quality control system that degrades mRNAs containing premature termination codons. Although NMD is well characterized in yeast and mammals, plant NMD is poorly understood. We have undertaken the functional dissection of NMD pathways in plants. Using an approach that allows rapid identification of plant NMD trans factors, we demonstrated that two plant NMD pathways coexist, one eliminates mRNAs with long 30UTRs, whereas a distinct pathway degrades mRNAs harbouring 30UTR-located introns. We showed that UPF1, UPF2 and SMG-7 are involved in both plant NMD pathways, whereas Mago and Y14 are required only for intron-based NMD. The molecular mechanism of long 30UTR-based plant NMD resembled yeast NMD, whereas the intron-based NMD was similar to mammalian NMD, suggesting that both pathways are evolutionarily conserved. Interestingly, the SMG-7 NMD component is targeted by NMD, suggesting that plant NMD is autoregulated. We propose that a complex, autoregulated NMD mechanism operated in stem eukaryotes, and that despite aspect of the mechanism being simplified in different lineages, feedback regulation was retained in all kingdoms.