title: Functional dissection and sequence of yeast HAP1 activator.
abstract: We present the DNA sequence and a functional dissection of the 1483 residue yeast activator HAP1. Salient results are, first, a single DNA binding domain (1-148) specifies binding to the two target sites of different sequence, UAS1 and CYC7. This domain contains a cysteine-rich zinc finger, and mutation of either of two cysteines abolishes binding to both sites. Second, mutations that specifically abolish binding to UAS1 or to CYC7 exist. These changes lie either in the residue immediately amino-terminal to the finger or in sequences carboxyl to the finger. Thus, both the base of the finger and carboxyl flanking residues are involved in specific DNA binding. Third, a distinct region (residues 245-445) mediates heme induction by masking the DNA binding domain in the absence of inducer; heme counteracts this masking, perhaps by interacting with a repeat sequence of metal binding character in this region. While sequences between 445 and 1308 have no obvious function, a highly acidic carboxyl terminus mediates transcriptional activation by HAP1.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
authors.forename: K
authors.initials: K
authors.lastname: Pfeifer
authors.forename: K S
authors.initials: KS
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Kogan
authors.forename: L
authors.initials: L
authors.lastname: Guarente
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002872:Chromosome Deletion; D003001:Cloning, Molecular; D003062:Codon; D004268:DNA-Binding Proteins / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics*; D005796:Genes; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D014176:Protein Biosynthesis; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D014158:Transcription, Genetic
chemical_list: D003062:Codon; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C058452:HAP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors