title: Transcription factor ZBP-89 cooperates with histone acetyltransferase p300 during butyrate activation of p21waf1 transcription in human cells.
abstract: Inducible p53-independent regulation of the cyclin-dependent kinase inhibitor p21(waf1) transcription is mediated through proximal GC-rich sites. Prior studies have shown that Sp1, Sp3, and the histone acetylase co-activator p300 are components of the complexes binding to these sites. Although Sp1 and Sp3 collaborate with p300, a direct interaction between Sp1 and p300 does not occur. This study sought to determine whether ZBP-89 rather than Sp1 is the direct target of p300 during butyrate induction of p21(waf1). ZBP-89 (BFCOL1, BERF-1, ZNF 148) is a Krüppel-type zinc finger transcription factor that binds to GC-rich elements and represses or activates known target genes. Adenoviral-mediated expression of ZBP-89 in HT-29 cells revealed that ZBP-89 potentiates butyrate induction of endogenous p21(waf1) gene expression. Further, cotransfection of a ZBP-89 expression vector with a 2.3-kilobase p21(waf1) reporter recapitulated the potentiation by butyrate. DNase I footprinting analysis of the human p21(waf1) promoter with recombinant ZBP-89 identified a binding site at -245 to -215. Electrophoretic mobility shift assays confirmed that both recombinant and endogenous ZBP-89 and Sp1 bind to this element. The potentiation was abolished in the presence of adenoviral protein E1A. Deletion of the N-terminal domain of ZBP-89 abolished the potentiation mediated by butyrate treatment. This same deletion mutant abolished the ZBP-89 interaction with p300. Cotransfection of p300 with ZBP-89 stimulated the p21(waf1) promoter in the absence of butyrate. p300 co-precipitated with ZBP-89 but not with Sp1, whereas ZBP-89 co-precipitated with Sp1. Together, these findings demonstrate that ZBP-89 also plays a critical role in butyrate activation of the p21(waf1) promoter and reveals preferential cooperation of this four-zinc finger transcription factor with p300.
authors.affiliation: Howard Hughes Medical Institute and the Departments of Internal Medicine and Physiology, University of Michigan, Ann Arbor, Mighican 48109, USA.
authors.forename: L
authors.initials: L
authors.lastname: Bai
authors.forename: J L
authors.initials: JL
authors.lastname: Merchant
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism*; D017500:Adenovirus E1A Proteins / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D002087:Butyrates / Q000494:pharmacology*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D016213:Cyclins / Q000235:genetics*; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051548:Histone Acetyltransferases; D006657:Histones; D006801:Humans; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D016335:Zinc Fingers; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor
chemical_list: D000123:Acetyltransferases; D017500:Adenovirus E1A Proteins; D002087:Butyrates; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases; D016213:Cyclins; D004268:DNA-Binding Proteins; D051548:Histone Acetyltransferases; D006657:Histones; D011994:Recombinant Proteins; D012097:Repressor Proteins; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C493956:CDKN1A protein, human; C110951:ZNF148 protein, human