Molecular connection between the TUTase URT1 and decapping activators

摘要: 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 network connecting several translational repressors/decapping activators including DECAPPING 5 (DCP5), ortholog of human LSM14 and yeast Scd6. A conserved Helical Leucine-rich Motif (HLM) within an intrinsically disordered region binds to LSm domain DCP5. This interaction connects additional decay factors like DDX6/Dhh1-like RNA helicases. The combination planta vitro analyses supports model explains how reduces accumulation oligo(A)-tailed mRNAs: first, by decapping second, because 3′ terminal uridines can hinder deadenylation. Importantly, preventing excessively deadenylated mRNAs avoids biogenesis illegitimate siRNAs silence endogenous perturb plant growth development.