p300 acts as a transcriptional coactivator for mammalian Notch-1.
Notch-1 belongs to a family of transmembrane receptor proteins that direct the decisions as to various cell fates. After ligand binding, a proteolytic cleavage step occurs and the intracellular part of Notch-1, Notch-1-IC, translocates into the nucleus, where it targets the DNA binding protein RBP-J kappa/CBF1. RBP-J kappa mediates repression through recruitment of a histone deacetylase-containing complex. The Notch-1-IC/RBP-J kappa complex overcomes repression and activates the transcription of Notch target genes. We have identified a novel domain in Notch-1-IC, the EP domain, which is indispensable for full transcriptional activation. This transactivation domain is localized adjacent to the ankyrin repeats of Notch-1-IC. In cotransfection experiments, Notch-1-IC-mediated transcriptional activation was inhibited by E1A12S and p53, two proteins, which interfere with the function of the common coactivator p300. Protein-protein interaction assays demonstrated the association of Notch-1-IC and the CH3 region of p300. In addition, the interaction of mammalian Notch-1-IC with p300 was destabilized after deletion of the EP domain of Notch-1-IC. Based on physical interaction with Notch-1-IC and coactivator functions of p300, we propose a model for Notch-1-mediated gene regulation via p300.
Oswald
F
F
Department of Internal Medicine, University of Ulm, Germany.
Täuber
B
B
Dobner
T
T
Bourteele
S
S
Kostezka
U
U
Adler
G
G
Liptay
S
S
Schmid
R M
RM
D017500:Adenovirus E1A Proteins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D001665:Binding Sites; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism; D050881:E1A-Associated p300 Protein; D024202:Electrophoretic Mobility Shift Assay; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008322:Mammals; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013347:Subcellular Fractions; D015534:Trans-Activators / Q000378:metabolism*; D000072056:Transcription Factor HES-1; D014157:Transcription Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D017500:Adenovirus E1A Proteins; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D050881:E1A-Associated p300 Protein; D049452:Green Fluorescent Proteins; D018398:Homeodomain Proteins; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D000072056:Transcription Factor HES-1; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; C489734:Hes1 protein, mouse; C497761:NOTCH1 protein, human; C497762:Notch1 protein, mouse; C497570:RBPJ protein, human; C497571:Rbpj protein, mouse; C078493:HES1 protein, human; C494361:Ep300 protein, mouse