title: Functional connections between mediator components and general transcription factors of Saccharomyces cerevisiae.
abstract: The yeast Gal11 protein is an important component of the Mediator complex in RNA polymerase II-directed transcription. Gal11 and the general transcription factor (TF) IIE are involved in regulation of the protein kinase activity of TFIIH that phosphorylates the carboxyl-terminal domain of RNA polymerase II. We have previously shown that Gal11 binds the small and large subunits of TFIIE at two Gal11 domains, A and B, respectively, which are important for normal function of Gal11 in vivo. Here we demonstrate that Gal11 binds directly to TFIIH through domain A in vitro. A null mutation in GAL11 caused lethality of cells when combined with temperature-sensitive mutations in the genes encoding TFIIE or the carboxyl-terminal domain kinase, indicating the presence of genetic interactions between Gal11 and these proteins. Mutational depletion of Gal11 or TFIIE caused inefficient opening of the transcription initiation region, but had no significant effect on TATA-binding protein occupancy of the TATA sequence in vivo. These results suggest that the functions of Gal11 and TFIIE are necessary after recruitment of TATA-binding protein to the TATA box presumably at the step of stable preinitiation complex formation and/or promoter melting. We illustrate genetic interactions between Gal11 and other Mediator components such as Med2 and Pgd1/Hrs1/Med3.
authors.affiliation: School of Health Sciences, Faculty of Medicine, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan. sakurai@kenroku.kanazawa-u.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Sakurai
authors.forename: T
authors.initials: T
authors.lastname: Fukasawa
mesh_terms: D001483:Base Sequence; D002846:Chromatography, Affinity; D004268:DNA-Binding Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000502:physiology*; D056892:Mediator Complex; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D035381:TATA-Binding Protein Associated Factors; D035181:TATA-Box Binding Protein; D015534:Trans-Activators / Q000502:physiology*; D035362:Transcription Factor TFIID; D051758:Transcription Factor TFIIH; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D019473:Transcription Factors, TFII
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C058337:GAL11 protein, S cerevisiae; D056892:Mediator Complex; D029701:Saccharomyces cerevisiae Proteins; C490039:TAF6 protein, S cerevisiae; D035381:TATA-Binding Protein Associated Factors; D035181:TATA-Box Binding Protein; D015534:Trans-Activators; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; C066644:transcription factor TFIIE; D051758:Transcription Factor TFIIH