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PubMed · 9372931

Subunit composition determines E2F DNA-binding site specificity.

Y Tao·R F Kassatly·W D Cress·J M Horowitz
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Abstract

The product of the retinoblastoma (Rb) susceptibility gene, Rb-1, regulates the activity of a wide variety of transcription factors, such as E2F, in a cell cycle-dependent fashion. E2F is a heterodimeric transcription factor composed of two subunits each encoded by one of two related gene families, denoted E2F and DP. Five E2F genes, E2F-1 through E2F-5, and two DP genes, DP-1 and DP-2, have been isolated from mammals, and heterodimeric complexes of these proteins are expressed in most, if not all, vertebrate cells. It is not yet clear whether E2F/DP complexes regulate overlapping and/or specific cellular genes. Moreover, little is known about whether Rb regulates all or a subset of E2F-dependent genes. Using recombinant E2F, DP, and Rb proteins prepared in baculovirus-infected cells and a repetitive immunoprecipitation-PCR procedure (CASTing), we have identified consensus DNA-binding sites for E2F-1/DP-1, E2F-1/DP-2, E2F-4/DP-1, and E2F-4/DP-2 complexes as well as an Rb/E2F-1/DP-1 trimeric complex. Our data indicate that (i) E2F, DP, and Rb proteins each influence the selection of E2F-binding sites; (ii) E2F sites differ with respect to their intrinsic DNA-bending properties; (iii) E2F/DP complexes induce distinct degrees of DNA bending; and (iv) complex-specific E2F sites selected in vitro function distinctly as regulators of cell cycle-dependent transcription in vivo. These data indicate that the specific sequence of an E2F site may determine its role in transcriptional regulation and suggest that Rb/E2F complexes may regulate subsets of E2F-dependent cellular genes.

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AnimalsBaculoviridaeBase SequenceBinding SitesCarrier ProteinsCell Cycle ProteinsCell LineConsensus SequenceCricetinaeDNADNA PrimersDNA-Binding ProteinsDimerizationE2F Transcription FactorsE2F1 Transcription FactorE2F4 Transcription FactorE2F5 Transcription FactorHumansIn Vitro TechniquesPolymerase Chain ReactionProtein ConformationRecombinant ProteinsRetinoblastoma ProteinRetinoblastoma-Binding Protein 1Transcription Factor DP1Transcription FactorsJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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Y Tao, R F Kassatly, W D Cress, J M Horowitz. 1997. Subunit composition determines E2F DNA-binding site specificity.. https://doi.org/10.1128/mcb.17.12.6994

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