title: Importance of general regulatory factors Rap1p, Abf1p and Reb1p for the activation of yeast fatty acid synthase genes FAS1 and FAS2.
abstract: The fatty acid synthase genes FAS1 and FAS2 of the yeast Saccharomyces cerevisiae are under transcriptional control of pathway-specific regulators of phospholipid biosynthesis. However, site-directed mutagenesis of the respective cis-acting elements upstream of FAS1 and FAS2 revealed that additional sequences activating both genes must exist. A deletion analysis of the FAS1 promoter lacking the previously characterized inositol/choline-responsive-element motif defined a region (nucleotides -760 to -850) responsible for most of the remaining activation potency. Gel-retardation experiments and in-vitro DNase footprint studies proved the binding of the general regulatory factors Rap1p, Abf1p and Reb1p to this FAS1 upstream region. Mutation of the respective binding sites led to a drop of gene activation to 8% of the wild-type level. Similarly, we also demonstrated the presence of a Reb1p-binding site upstream of FAS2 and its importance for gene activation. Thus, in addition to the previously characterized FAS-binding factor 1 interacting with the inositol/choline-responsive-element motif, a second motif common to the promoter regions of both FAS genes could be identified. Transcription of yeast fatty acid synthase genes is therefore subjected to both the pathway-specific control affecting genes of phospholipid biosynthesis and to the activation by general transcription factors allowing a sufficiently high level of constitutive gene expression.
authors.affiliation: Institut für Mikrobiologie, Biochemie und Genetik, Universität Erlangen/Nürnberg, Germany.
authors.forename: H J
authors.initials: HJ
authors.lastname: Schüller
authors.forename: A
authors.initials: A
authors.lastname: Schütz
authors.forename: S
authors.initials: S
authors.lastname: Knab
authors.forename: B
authors.initials: B
authors.lastname: Hoffmann
authors.forename: E
authors.initials: E
authors.lastname: Schweizer
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D004271:DNA, Fungal / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D064429:Fatty Acid Synthases / Q000096:biosynthesis* / Q000235:genetics; D005656:Fungal Proteins / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D020668:rap GTP-Binding Proteins
chemical_list: C061886:ABF1 protein, S cerevisiae; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009838:Oligodeoxyribonucleotides; C065681:REB1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D064429:Fatty Acid Synthases; D019204:GTP-Binding Proteins; D020668:rap GTP-Binding Proteins