title: The transcriptional activators of the PHO regulon, Pho4p and Pho2p, interact directly with each other and with components of the basal transcription machinery in Saccharomyces cerevisiae.
abstract: The transcriptional regulators Pho4p and Pho2p are involved in transcription of several genes in the PHO regulon of Saccharomyces cerevisiae. Genetic evidence with temperature-sensitive pho4 and pho2 mutants suggested that Pho4p and Pho2p interact with each other. Immunoprecipitation experiments showed that Pho4p and Pho2p form a complex on a 36-bp sequence bearing an upstream activation site (UAS) and protein binding assays indicated that these proteins interact directly. DNA-binding experiments with crude extracts prepared from yeast strains expressing T7-PHO4, encoding Pho4p tagged with the T7 epitope, indicated that Pho2p interacts with T7-Pho4p and enhances the binding affinity of T7-Pho4p to the UAS. Protein binding experiments also showed that both Pho4p and Pho2p could bind with the general transcription factors, TBP, TFIIB, and TFIIEbeta, suggesting that the Pho4p-Pho2p complex bound to the UAS activates transcription of the PHO genes by direct interaction with the general transcription factors.
authors.affiliation: Department of Biotechnology, Faculty of Engineering, Osaka University, Suita.
authors.forename: J P
authors.initials: JP
authors.lastname: Magbanua
authors.forename: N
authors.initials: N
authors.lastname: Ogawa
authors.forename: S
authors.initials: S
authors.lastname: Harashima
authors.forename: Y
authors.initials: Y
authors.lastname: Oshima
mesh_terms: D001481:Basal Metabolism; D004271:DNA, Fungal / Q000235:genetics; D005800:Genes, Fungal; D018085:Regulon; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D004271:DNA, Fungal; D014157:Transcription Factors