title: Efficiency of the pioneer round of translation affects the cellular site of nonsense-mediated mRNA decay.
abstract: In mammalian cells, nonsense-mediated mRNA decay (NMD) is a consequence of nonsense codon recognition during a pioneer round of translation. This round can occur largely before or largely after the release of newly synthesized mRNA from nuclei, depending on the mRNA, and likely utilizes cytoplasmic ribosomes. We show that increasing the cellular concentration of the splicing factor SF2/ASF augments the efficiency of NMD and ultimately shifts NMD that takes place after mRNA export to the cytoplasm to NMD that occurs before mRNA release from nuclei. These changes are accompanied by an increased association of pioneer translation initiation complexes with SF2/ASF, translationally active ribosomes, and the translational activator TAP. Increased TAP binding correlates with increased SF2/ASF binding, but not increased REF/Aly or Y14 binding. Our results uncover an additional role for SF2/ASF and indicate that the efficiency of the pioneer round of translation influences the efficiency of subsequent rounds of translation.
authors.affiliation: Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA.
authors.forename: Hanae
authors.initials: H
authors.lastname: Sato
authors.forename: Nao
authors.initials: N
authors.lastname: Hosoda
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Maquat
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology; D000818:Animals; D019556:COS Cells; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D018389:Codon, Nonsense / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000502:physiology; D020871:RNA Stability / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D000068103:Serine-Arginine Splicing Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C105242:ALYREF protein, human; D018389:Codon, Nonsense; D009687:Nuclear Proteins; C406243:RBM8A protein, human; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D000068103:Serine-Arginine Splicing Factors