Minimal activators that bind to the KIX domain of p300/CBP identified by phage display screening.
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.
Frangioni
J V
JV
The Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
LaRiccia
L M
LM
Cantley
L C
LC
Montminy
M R
MR
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
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