title: Minimal activators that bind to the KIX domain of p300/CBP identified by phage display screening.
abstract: Human gene therapy approaches involving transcription factors often rely on artificial activation domains for transcriptional activation. These domains are often large (e.g., 80 amino acids for VP16), recruit multiple co-activation complexes at once, and offer no fine control over the level of transcription. In an attempt to understand the sequence and structural requirements of a minimal mammalian activator, we employed a molecular diversity approach with a peptide phage display library composed of random eight-amino acid peptides. Using the KIX domain of the mammalian co-activators p300 and CBP as target, we discovered a family of synthetic binding peptides. These peptides share significant homology with natural KIX domain ligands, and are shown to bind an overlapping, yet distinct, surface of p300/CREB-binding protein (CBP). When fused to a heterologous DNA binding domain, these synthetic peptides function as titratable, modular, and potent transcriptional activators in living cells through specific recruitment of p300/CBP, with the level of transcriptional activation proportional to the affinity of the synthetic peptide for the KIX domain. Taken together, our data demonstrate that a molecular diversity approach can be used to discover minimal, co-activator domain-specific synthetic activators, and that transcriptional activation can be modulated as desired at the level of co-activator recruitment.
authors.affiliation: The Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
authors.forename: J V
authors.initials: JV
authors.lastname: Frangioni
authors.forename: L M
authors.initials: LM
authors.lastname: LaRiccia
authors.forename: L C
authors.initials: LC
authors.lastname: Cantley
authors.forename: M R
authors.initials: MR
authors.lastname: Montminy
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D050882:CREB-Binding Protein; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D050881:E1A-Associated p300 Protein; D017930:Genes, Reporter; D051379:Mice; D008958:Models, Molecular; D009687:Nuclear Proteins / Q000737:chemistry* / Q000378:metabolism*; D009842:Oligopeptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D019151:Peptide Library; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D015533:Transcriptional Activation; D014162:Transfection
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009842:Oligopeptides; D019151:Peptide Library; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D050882:CREB-Binding Protein; C494364:Crebbp protein, mouse; D050881:E1A-Associated p300 Protein; C494361:Ep300 protein, mouse