Beyond their canonical function in nucleocytoplasmic exchanges, nuclear pore complexes (NPCs) regulate the expression of protein-coding genes. Here, we have implemented transcriptomic and molecular methods to specifically address the impact of the NPC on retroelements, which are present in multiple copies in genomes. We report a novel function for the Nup84 complex, a core NPC building block, in specifically restricting the transcription of LTR-retrotransposons in yeast. Nup84 complex-dependent repression impacts both Copia and Gypsy Ty LTR-retrotransposons, all over the S. cerevisiae genome. Mechanistically, the Nup84 complex restricts the transcription of Ty1, the most active yeast retrotransposon, through the tethering of the SUMO-deconjugating enzyme Ulp1 to NPCs. Strikingly, the modest accumulation of Ty1 RNAs caused by Nup84 complex loss-of-function is sufficient to trigger an important increase of Ty1 cDNA levels, resulting in massive Ty1 retrotransposition. Altogether, our studies expand our understanding of the complex interactions between retrotransposons and the NPC, and highlight the importance for the cells to keep retrotransposon under tight transcriptional control.

中文翻译：

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核孔亚复合物通​​过限制Ty反转录转座子的转录来限制其传播

除了它们在核质交换中的典型功能外，核孔复合物（NPC）还调节蛋白质编码基因的表达。在这里，我们已经实施了转录组学和分子方法，以专门解决NPC对反转录元素的影响，反转录元素存在于基因组的多个副本中。我们报告了Nup84复合物，NPC的核心构建块，在限制酵母中LTR-逆转座子转录的新功能。Nup84依赖复合物的阻遏作用影响啤酒酵母基因组中的Copia和吉普赛Ty LTR-逆转座子。从机理上讲，Nup84复合物通过SUMO解偶联酶Ulp1与NPC的连接，限制了最具活性的酵母逆转录转座子Ty1的转录。惊人地 Nup84复合物功能丧失引起的Ty1 RNA的适度积累足以触发Ty1 cDNA水平的重要增加，从而导致大量Ty1逆转录。总而言之，我们的研究扩大了我们对逆转座子与NPC之间复杂相互作用的理解，并突出了使细胞保持逆转座子处于严格转录控制之下的重要性。