title: Polyamine-responsive ribosomal arrest at the stop codon of an upstream open reading frame of the AdoMetDC1 gene triggers nonsense-mediated mRNA decay in Arabidopsis thaliana.
abstract: During mRNA translation, nascent peptides with certain specific sequences cause arrest of ribosomes that have synthesized themselves. In some cases, such ribosomal arrest is coupled with mRNA decay. In yeast, mRNA quality control systems have been shown to be involved in mRNA decay associated with ribosomal arrest. However, a link between ribosomal arrest and mRNA quality control systems has not been found in multicellular organisms. In this study, we aimed to explore the relationship between ribosomal arrest and mRNA decay in plants. For this purpose, we used an upstream open reading frame (uORF) of the Arabidopsis thaliana AdoMetDC1 gene, in which the uORF-encoded peptide is involved in polyamine-responsive translational repression of the main coding sequence. Our in vitro analyses revealed that the AdoMetDC1 uORF-encoded peptide caused ribosomal arrest at the uORF stop codon in response to polyamine. Using transgenic calli harboring an AdoMetDC1 uORF-containing reporter gene, we showed that polyamine promoted mRNA decay in a uORF sequence-dependent manner. These results suggest that the polyamine-responsive ribosomal arrest mediated by the uORF-encoded peptide is coupled with mRNA decay. Our results also showed that the polyamine-responsive acceleration of mRNA decay was compromised by defects in factors that are essential for nonsense-mediated mRNA decay (NMD), an mRNA quality control system that degrades mRNAs with premature stop codons, suggesting that NMD is involved in AdoMetDC1 uORF peptide-mediated mRNA decay. Collectively, these findings suggest that AdoMetDC1 uORF peptide-mediated ribosomal arrest at the uORF stop codon induces NMD.
authors.affiliation: Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan Present address: Chifure Corporation, Kawagoe, 350-0833 Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Uchiyama-Kadokura
authors.affiliation: Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan.
authors.forename: Karin
authors.initials: K
authors.lastname: Murakami
authors.affiliation: Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan Present address: SRD Corporation, Chuo-ku, Tokyo, 104-0032 Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Takemoto
authors.affiliation: Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan Present address: Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639 Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Koyanagi
authors.affiliation: Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan Present address: Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Sapporo, 062-8517 Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Murota
authors.affiliation: Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Naito
authors.affiliation: Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan onouchi@abs.agr.hokudai.ac.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Onouchi
mesh_terms: D012437:Adenosylmethionine Decarboxylase / Q000235:genetics*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics; D018389:Codon, Nonsense / Q000235:genetics; D018388:Codon, Terminator / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D009154:Mutation; D059365:Nonsense Mediated mRNA Decay / Q000235:genetics*; D016366:Open Reading Frames / Q000235:genetics; D030821:Plants, Genetically Modified; D011073:Polyamines / Q000494:pharmacology*; D012270:Ribosomes / Q000187:drug effects / Q000235:genetics*; D020506:Untranslated Regions / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D018389:Codon, Nonsense; D018388:Codon, Terminator; D011073:Polyamines; D020506:Untranslated Regions; D012437:Adenosylmethionine Decarboxylase
keywords: Arabidopsis thaliana; Nonsense-mediated mRNA decay; Polyamine; Ribosome; Translational regulation; Upstream ORF