title: Polypyrimidine tract binding protein regulates IRES-mediated gene expression during apoptosis.
abstract: During apoptosis there is a substantial reduction in the rate of protein synthesis, and yet some mRNAs avoid this translational inhibition. To determine the impact that receptor-mediated cell death has on the translational efficiency of a large number of mRNAs, translational profiling was performed on MCF7 cells treated with the apoptosis-inducing ligand TRAIL. Our data indicate that approximately 3% of mRNAs remain associated with the polysomes in apoptotic cells, and genes that are involved in transcription, chromatin modification/remodeling, and the Notch signaling pathway are particularly prevalent among the mRNAs that evade translational inhibition. Internal ribosome entry segments (IRESs) were identified in several of the mRNAs that remained associated with the polysomes during apoptosis, and, importantly, these IRESs functioned efficiently in apoptotic cells. Finally, the data showed that polypyrimidine tract binding protein (PTB, a known IRES trans-acting factor or ITAF) is pivotal in regulating the apoptotic process by controlling IRES function.
authors.affiliation: School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom. martin.bushell@nottingham.ac.uk
authors.forename: Martin
authors.initials: M
authors.lastname: Bushell
authors.forename: Mark
authors.initials: M
authors.lastname: Stoneley
authors.forename: Yi Wen
authors.initials: YW
authors.lastname: Kong
authors.forename: Tiffany L
authors.initials: TL
authors.lastname: Hamilton
authors.forename: Keith A
authors.initials: KA
authors.lastname: Spriggs
authors.forename: Helen C
authors.initials: HC
authors.lastname: Dobbyn
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Qin
authors.forename: Peter
authors.initials: P
authors.lastname: Sarnow
authors.forename: Anne E
authors.initials: AE
authors.lastname: Willis
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000494:pharmacology; D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D008562:Membrane Glycoproteins / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism; D038941:Polypyrimidine Tract-Binding Protein / Q000502:physiology*; D011132:Polyribosomes / Q000187:drug effects / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D038621:Regulatory Sequences, Ribonucleic Acid / Q000235:genetics*; D012270:Ribosomes / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D020121:5' Untranslated Regions; D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C079950:CSDE1 protein, human; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C087000:EIF4EBP1 protein, human; C111931:ELF4 protein, human; D008562:Membrane Glycoproteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D038621:Regulatory Sequences, Ribonucleic Acid; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D038941:Polypyrimidine Tract-Binding Protein; D011065:Poly(ADP-ribose) Polymerases