title: Antizyme frameshifting as a functional probe of eukaryotic translational termination.
abstract: Translation termination in eukaryotes is mediated by the release factors eRF1 and eRF3, but mechanisms of the interplay between these factors are not fully understood, due partly to the difficulty of measuring termination on eukaryotic mRNAs. Here, we describe an in vitro system for the assay of termination using competition with programmed frameshifting at the recoding signal of mammalian antizyme. The efficiency of antizyme frameshifting in rabbit reticulocyte lysates was reduced by addition of recombinant rabbit eRF1 and eRF3 in a synergistic manner. Addition of suppressor tRNA to this assay system revealed competition with a third event, stop codon readthrough. Using these assays, we demonstrated that an eRF3 mutation at the GTPase domain repressed termination in a dominant negative fashion probably by binding to eRF1. The effect of the release factors and the suppressor tRNA showed that the stop codon at the antizyme frameshift site is relatively inefficient compared to either the natural termination signals at the end of protein coding sequences or the readthrough signal from a plant virus. The system affords a convenient assay for release factor activity and has provided some novel views of the mechanism of antizyme frameshifting.
authors.affiliation: Department of Biochemistry II, The Jikei University, School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan.
authors.forename: Zemfira N
authors.initials: ZN
authors.lastname: Karamysheva
authors.forename: Andrey L
authors.initials: AL
authors.lastname: Karamyshev
authors.forename: Koichi
authors.initials: K
authors.lastname: Ito
authors.forename: Takashi
authors.initials: T
authors.lastname: Yokogawa
authors.forename: Kazuya
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Senya
authors.initials: S
authors.lastname: Matsufuji
mesh_terms: D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002474:Cell-Free System / Q000378:metabolism; D018388:Codon, Terminator / Q000235:genetics; D018965:Frameshifting, Ribosomal; D008969:Molecular Sequence Data; D009154:Mutation; D065108:Ornithine Decarboxylase Inhibitors; D010443:Peptide Chain Termination, Translational / Q000235:genetics*; D010454:Peptide Termination Factors / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D011817:Rabbits; D012156:Reticulocytes
chemical_list: D018388:Codon, Terminator; D065108:Ornithine Decarboxylase Inhibitors; D010454:Peptide Termination Factors; D011506:Proteins; D012333:RNA, Messenger; C031017:ornithine decarboxylase antizyme; C087971:peptide-chain-release factor 3