title: Yeast Cyc8p and Tup1p proteins function as coactivators for transcription of Stp1/2p-dependent amino acid transporter genes.
abstract: The yeast Cyc8p-Tup1p complex is known to serve primarily as a transcriptional corepressor in a variety of biological processes. However, less is known about its function as a coactivator. Herein, we found tryptophan transporter genes, TAT1 and TAT2, that, when overexpressed, suppressed the slow growth of Δcyc8. We observed that the addition of tryptophan to Δcyc8 cultures partially restored cell growth, and the deletion of CYC8 and TUP1 reduced transcriptional levels of TAT1 and TAT2. Tup1p bound to the promoter region of TAT1 and TAT2 genes that were dependent on STP1 and STP2 (encoding DNA-binding activator proteins) for expression. Similarly, transcription of the other Stp1/2p-dependent amino acid transporter (AAT) genes also required CYC8 and TUP1 gene functions. These data indicate that Cyc8p-Tup1p plays a role as a transcriptional coactivator for AAT genes via Stp1/2p activators and that lowering intracellular tryptophan by CYC8 deletion causes slow growth.
authors.affiliation: Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Tanaka
authors.affiliation: Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan. Electronic address: y_mukai@nagahama-i-bio.ac.jp.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Mukai
mesh_terms: D026905:Amino Acid Transport Systems / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D009687:Nuclear Proteins / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D026905:Amino Acid Transport Systems; C065455:CYC8 protein, S cerevisiae; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C074632:STP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C421606:Stp2 protein, S cerevisiae; C470089:TAT1 protein, S cerevisiae; C429825:TAT2 protein, S cerevisiae; C066502:TUP1 protein, S cerevisiae; D014157:Transcription Factors
keywords: Amino acid transporter; CYC8; TUP1; Transcriptional coactivator; Yeast