National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Nat Commun. 2017 Mar 3;8:14651. doi: 10.1038/ncomms14651.
Transposable elements constitute a substantial portion of eukaryotic genomes and contribute to genomic variation, function, and evolution. Miniature inverted-repeat transposable elements (MITEs), as DNA transposons, are widely distributed in plant and animal genomes. Previous studies have suggested that retrotransposons act as translational regulators; however, it remains unknown how host mRNAs are influenced by DNA transposons. Here we report a translational repression mechanism mediated by a stowaway-like MITE (sMITE) embedded in the 3'-untranslated region (3'-UTR) of Ghd2, a member of the CCT (CONSTANS [CO], CO-LIKE and TIMING OF CAB1) gene family in rice. Ghd2 regulates important agronomic traits, including grain number, plant height and heading date. Interestingly, the translational repression of Ghd2 by the sMITE mainly relies on Dicer-like 3a (OsDCL3a). Furthermore, other MITEs in the 3'-UTRs of different rice genes exhibit a similar effect on translational repression, thus suggesting that MITEs may exert a general regulatory function at the translational level.
转座元件构成真核生物基因组的重要组成部分，有助于基因组变异、功能和进化。微型反向重复转座元件（MITEs）作为 DNA 转座子，广泛分布于动植物基因组中。先前的研究表明，反转录转座子作为翻译调节剂发挥作用；然而，DNA 转座子如何影响宿主 mRNA 仍不清楚。在这里，我们报道了一种由嵌入水稻 CCT（CONSTANS [CO]、CO-LIKE 和 TIMING OF CAB1）基因家族成员 Ghd2 的 3'非翻译区（3'-UTR）中的寄居样 MITE（sMITE）介导的翻译抑制机制。Ghd2 调节重要的农艺性状，包括粒数、株高和抽穗期。有趣的是，sMITE 对 Ghd2 的翻译抑制主要依赖于 Dicer-like 3a（OsDCL3a）。此外，不同水稻基因 3'-UTR 中的其他 MITEs 对翻译抑制也表现出相似的效果，因此表明 MITEs 可能在翻译水平上发挥普遍的调节功能。
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