title: Evidence for the presence of a guanine quadruplex forming region within a polypurine tract of the hypoxia inducible factor 1alpha promoter.
abstract: The promoter of the hypoxia inducible factor 1 alpha (HIF-1alpha) gene has a polypurine/polypyrimidine tract (-65 to -85) overlapping or adjacent to several putative transcription factor binding sites, and we found that mutagenesis of this region diminished basal HIF-1alpha expression. Oligonucleotides representing this region of the HIF-1alpha promoter were analyzed by electrophoretic mobility shift, chemical probing, circular dichroism, and DNA polymerase arrest assays. The guanine-rich strand was found to form a parallel, unimolecular quadruplex in the presence of potassium that was further stabilized by two known quadruplex binding compounds, the cationic porphyrin TmPyP4 and the natural product telomestatin, while TmPyP2, a positional isomer of TmPyP4, did not stabilize quadruplex formation. These data suggest that a quadruplex structure may form in a region of the HIF-1alpha promoter that regulates basal HIF-1alpha expression.
authors.affiliation: Arizona Cancer Center, University of Arizona, 1515 North Campbell Avenue, Tucson, Arizona 85724-5024, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: De Armond
authors.forename: Stacey
authors.initials: S
authors.lastname: Wood
authors.forename: Daekyu
authors.initials: D
authors.lastname: Sun
authors.forename: Laurence H
authors.initials: LH
authors.lastname: Hurley
authors.forename: Scot W
authors.initials: SW
authors.lastname: Ebbinghaus
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D005786:Gene Expression Regulation; D006147:Guanine / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D006147:Guanine