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The Apaf-1 internal ribosome entry segment attains the correct structural conformation for function via interactions with PTB and unr.

Sally A Mitchell·Keith A Spriggs·Mark J Coldwell·Richard J Jackson·Anne E Willis
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Abstract

We have shown previously that polypyrimidine tract binding protein 1 (PTB) binds and activates the Apaf-1 internal ribosome entry segment (IRES) when the protein upstream of N-ras (unr) is prebound. Here we show that the Apaf-1 IRES is highly active in neuronal-derived cell lines due to the presence of the neuronal-enhanced version of PTB, nPTB. The unr and PTB/nPTB binding sites have been located on the Apaf-1 IRES RNA, and a structural model for the IRES bound to these proteins has been derived. The ribosome landing site has been located to a single-stranded region, and this is generated by the binding of the nPTB and unr to the RNA. These data suggest that unr and nPTB act as RNA chaperones by changing the structure of the IRES into one that permits translation initiation.

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Apoptotic Protease-Activating Factor 1Base SequenceBinding SitesBlotting, WesternCell LineDNA-Binding ProteinsDose-Response Relationship, DrugElectrophoresis, Polyacrylamide GelGene DeletionHeLa CellsHumansKineticsModels, BiologicalModels, GeneticMolecular Sequence DataMutagenesisMutationNeuronsNucleic Acid ConformationPhenotypePolymerase Chain ReactionPolypyrimidine Tract-Binding ProteinProtein BindingProtein BiosynthesisProtein ConformationProteinsRNA-Binding ProteinsReverse Transcriptase Polymerase Chain ReactionRibosomesTranscription, GeneticTransfectionUltraviolet RaysJournal ArticleResearch Support, Non-U.S. Gov't

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Sally A Mitchell, Keith A Spriggs, Mark J Coldwell, Richard J Jackson, Anne E Willis. 2003. The Apaf-1 internal ribosome entry segment attains the correct structural conformation for function via interactions with PTB and unr.. https://doi.org/10.1016/s1097-2765(03)00093-5

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