title: Evidence that Gal11 protein is a target of the Gal4 activation domain in the mediator.
abstract: The mediator is an approximately 20 protein complex that is essential for the transcription of most genes in yeast. It is contacted by a number of gene-specific activators, but the details of these interactions are not well understood in most cases. Here, evidence is presented that the mediator component Gal11 represents at least one target of the Gal4 activation domain (AD). Deletion of Gal11 is shown to decrease the affinity of the Gal4 AD for the mediator, and direct binding of an N-terminal domain of Gal11 with the Gal4 AD is demonstrated. Quantitative studies, however, indicate that the K(D) of the 1:1 Gal4 AD--Gal11 complex is modest. Combined with in vivo data showing that Delta gal11 cells exhibit reduced, but still significant, Gal4-mediated gene expression, these results suggest that the dimeric activator might also contact another protein in the mediator in addition to Gal11.
authors.affiliation: Department of Internal Medicine, Ryburn Center for Molecular Cardiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-8573, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Jeong
authors.forename: S H
authors.initials: SH
authors.lastname: Yang
authors.forename: Y
authors.initials: Y
authors.lastname: Xie
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: S A
authors.initials: SA
authors.lastname: Johnston
authors.forename: T
authors.initials: T
authors.lastname: Kodadek
mesh_terms: D001667:Binding, Competitive; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D056892:Mediator Complex; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C058337:GAL11 protein, S cerevisiae; C052130:GAL4 protein, S cerevisiae; C055002:GAL80 protein, S cerevisiae; D056892:Mediator Complex; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors