title: Developmental and hormonal regulation of sunflower helianthinin genes: proximal promoter sequences confer regionalized seed expression.
abstract: DNA elements involved in the regulation of two sunflower helianthinin genes were identified by analysis of beta-glucuronidase (GUS) expression in transgenic tobacco driven by sequences derived from the 5' upstream regions of these genes. A 2.4-kb upstream region of the helianthinin gene HaG3-A conferred rigorous developmental GUS expression in transgenic tobacco seeds with no significant GUS activity in nonembryonic tissues. Regions of the helianthinin upstream regulatory ensemble (URE) conferred ectopic expression in nonembryonic tissues when analyzed outside of the context of the complete helianthinin regulatory complex. A proximal promoter region was identified that conferred significant GUS expression in seeds but not in leaves of transgenic tobacco. Three sequence motifs that bind to seed nuclear proteins were identified in the proximal promoter region; mutations in these motifs significantly reduced the level of nuclear protein binding. Another important class of cis-regulatory elements was identified in the helianthinin URE that conferred abscisic acid-responsive GUS expression. In the full-length helianthinin URE, these elements only responded to abscisic acid in the developing seed, suggesting that the helianthinin gene contains additional regulatory elements, possibly in the proximal promoter region, that ensure hierarchical control in the developing seed.
authors.affiliation: Department of Biology, Texas A & M University, College Station 77843.
authors.forename: A N
authors.initials: AN
authors.lastname: Nunberg
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.forename: M A
authors.initials: MA
authors.lastname: Bogue
authors.forename: J
authors.initials: J
authors.lastname: Vivekananda
authors.forename: A S
authors.initials: AS
authors.lastname: Reddy
authors.forename: T L
authors.initials: TL
authors.lastname: Thomas
mesh_terms: D055516:2S Albumins, Plant; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D005786:Gene Expression Regulation; D005966:Glucuronidase / Q000096:biosynthesis / Q000378:metabolism; D006368:Helianthus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics*; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D055314:Seed Storage Proteins; D012639:Seeds / Q000378:metabolism; D016385:TATA Box; D014026:Nicotiana / Q000378:metabolism
chemical_list: D055516:2S Albumins, Plant; D009687:Nuclear Proteins; D010940:Plant Proteins; D055314:Seed Storage Proteins; D004247:DNA; D005966:Glucuronidase