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bioRxiv · 10.1101/409490

A SKI subcomplex specifically required for the degradation of ribosome-free RNA regions

Fromont-Racine, M.·Zhang, E.·Khanna, V.·Namane, A.·Doyen, A.·Dacheux, E.·Turcotte, B.·Jacquier, A.
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Abstract

The Ski2-Ski3-Ski8 (SKI) complex assists the RNA exosome during the 3-5 degradation of cytoplasmic transcripts. Previous reports showed that the SKI complex is involved in the 3-5 degradation of mRNA, including 3 untranslated regions (UTRs), devoid of ribosomes. Paradoxically, we recently showed that the SKI complex directly interacts with ribosomes during the co-translational mRNA decay and that this interaction is necessary for its RNA degradation promoting activity. Here, we characterized a new SKI-associated factor, Ska1, which antagonizes the SKI-ribosome interaction. We showed that the SKI-Ska1-subcomplex is specifically involved in the degradation of ribosome-free RNA regions such as long mRNA 3UTRs and cytoplasmic lncRNAs. We propose a model in which the SKI-exosome complex first targets ribosome-free RNA 3ends in its Ska1-associated form. When the complex reaches the mRNA coding sequence, the Ska1-SKI-exosome complex is exchanged for the SKI-exosome, which interacts directly with ribosomes in order to resume the degradation process.

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Fromont-Racine, M., Zhang, E., Khanna, V., Namane, A., Doyen, A., Dacheux, E., Turcotte, B., Jacquier, A.. 2018-09-05. A SKI subcomplex specifically required for the degradation of ribosome-free RNA regions. https://doi.org/10.1101/409490

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