title: Binding capacity of human YB-1 protein for RNA containing 8-oxoguanine.
abstract: 8-oxoguanine (8-oxo-7,8-dihydroguanine) is generated in the cellular nucleotide pool as well as in nucleic acids, by the action of oxygen radicals produced in cells. 8-oxoguanine has the potential to pair with both cytosine and adenine, and thus, the persistence of this base in messenger RNA would cause translational errors. To prevent such an outcome, organisms should have mechanisms for preventing the misincorporation of 8-oxoguanine-containing nucleotide into RNA and for removing 8-oxoguanine-containing RNA from processes of translation. We now report that mammalian Y box-binding protein 1 (YB-1 protein) possesses the activity to bind specifically to RNA containing 8-oxoguanine. On incubation with a purified preparation of YB-1 protein, 8-oxoguanine-containing RNA forms stable complexes with the protein while normal RNA scarcely forms such a complex. Using a series of deletion mutants which produce altered forms of YB-1 protein lacking some parts of the sequence, domains of the protein necessary for RNA binding were identified. Escherichia coli cells expressing normal or truncated forms of YB-1 protein with the binding capacity acquire resistance against paraquat, a drug that induces oxidative stress in cells, whereas cells with truncated proteins lacking such an activity do not. YB-1 protein may disturb the bacterial system in recognizing oxidatively damaged RNA, thus exerting a dominant negative effect on cell growth. We propose that YB-1 protein may discriminate the oxidized RNA molecule from normal ones, thus contributing to the high fidelity of translation in cells.
authors.affiliation: Department of Medical Biochemistry, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan. hiroshi@med.kyushu-u.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hayakawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Uchiumi
authors.forename: Takao
authors.initials: T
authors.lastname: Fukuda
authors.forename: Megumi
authors.initials: M
authors.lastname: Ashizuka
authors.forename: Kimitoshi
authors.initials: K
authors.lastname: Kohno
authors.forename: Michihiko
authors.initials: M
authors.lastname: Kuwano
authors.forename: Mutsuo
authors.initials: M
authors.lastname: Sekiguchi
mesh_terms: D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D015169:Colony Count, Microbial; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D006131:Growth Inhibitors / Q000494:pharmacology; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism*; D006801:Humans; D008826:Microbial Sensitivity Tests; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D010269:Paraquat / Q000494:pharmacology; D010957:Plasmids / Q000187:drug effects / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000494:pharmacology; D017384:Sequence Deletion; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D006131:Growth Inhibitors; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; C024829:8-hydroxyguanine; D006147:Guanine; D010269:Paraquat