title: Inhibition of E2F-4/DP-1-stimulated transcription by p202.
abstract: The interferon (IFN)-inducible proteins mediate activities of the interferons including the cell growth-regulatory activity. We have shown that p202, an IFN-inducible 52kDa primarily nuclear phosphoprotein whose expression in transfected cells inhibits cell proliferation, interacts with the retinoblastoma tumor suppressor protein (pRb) and the transcription factor E2F (E2F-1/ DP-1) in vitro and in vivo. p202 was shown to inhibit E2F-1/DP-1-stimulated transcription of a reporter gene and of endogenous genes. Here we report that expression of p202 inhibited E2F-4/DP-1-stimulated transcription of a reporter gene in transfected cells. Furthermore, this inhibition was associated with the inhibition of the sequence-specific DNA-binding of E2F-4 both in complex with the pocket proteins p107 or p130 and in its 'free' form in vitro. p202 bound to p107 and p130 in vitro and in vivo and also associated with E2F-4, supporting the notion that complexes containing p107/E2F-4 or p130/ E2F-4 and p202 exist in vivo. Moreover, cotransfection of E2F-4-encoding plasmid in AKR-2B cells overcame p202-mediated inhibition of cell growth, raising the possibility that p202 contributes to cell growth inhibition by the interferons, at least in part, by modulating E2F-4-mediated transcription.
authors.affiliation: Department of Molecular Oncology, The University of Texas MD Anderson Cancer Center, Houston 77030, USA.
authors.forename: D
authors.initials: D
authors.lastname: Choubey
authors.forename: J U
authors.initials: JU
authors.lastname: Gutterman
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002455:Cell Division; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D050704:E2F4 Transcription Factor; D005260:Female; D017930:Genes, Reporter; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012156:Reticulocytes / Q000378:metabolism; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured; D000071857:Tumor Suppressor p53-Binding Protein 1; D002583:Uterine Cervical Neoplasms
chemical_list: C533431:Arid4a protein, mouse; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D050704:E2F4 Transcription Factor; C493762:E2F4 protein, human; C493754:E2f1 protein, mouse; C493763:E2f4 protein, mouse; C092537:Ifi202b protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D056465:Retinoblastoma-Binding Protein 1; C493735:TFDP1 protein, human; C498301:TP53BP1 protein, human; C493736:Tfdp1 protein, mouse; D050680:Transcription Factor DP1; D014157:Transcription Factors; D000071857:Tumor Suppressor p53-Binding Protein 1