Molecular connection between the TUTase URT1 and decapping activators

Hélène Scheer, Caroline de Almeida, Emilie Ferrier, Laure Poirier, David Pflieger, François M Sement, Sandrine Koechler, Christina Piermaria, Johana Chicher, Lauriane Kuhn, Philippe Hammann, Hélène Zuber, Dominique Gagliardi

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Received Date: 12th May 20

Uridylation is a widespread modification destabilizing eukaryotic mRNAs. Yet, molecular mechanisms underlying TUTase-mediated mRNA degradation remain mostly unresolved. Here, we report that the Arabidopsis TUTase URT1 participates in a molecular network connecting several translational repressors/decapping activators including DECAPPING 5 (DCP5), the Arabidopsis ortholog of human LSM14 and yeast Scd6. A conserved Helical Leucine-rich Motif (HLM) within an intrinsically disordered region of URT1 binds to the LSm domain of DCP5. This interaction connects URT1 to additional decay factors like DDX6/Dhh1-like RNA helicases. The combination of in planta and in vitro analyses supports a model that explains how URT1 reduces the accumulation of oligo(A)-tailed mRNAs: first, by connecting decapping factors and second, because 3’ terminal uridines can intrinsically hinder deadenylation. Importantly, preventing the accumulation of excessively deadenylated mRNAs in Arabidopsis avoids the biogenesis of illegitimate siRNAs that silence endogenous mRNAs and perturb plant growth and development.

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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.

Nature Communications

Nature Research, Springer Nature