title: Characterization of a shoot-specific, GA3- and ABA-regulated gene from tomato.
abstract: A tomato (Lycopersicon esculentum) gene (GAST1) that encodes an RNA whose abundance increases > 20-fold in shoots of the GA-deficient gib1 mutant following spraying with GA3 has been characterized. An increase in GAST1 RNA levels is detectable 2 h after treatment and levels continue to increase for at least an additional 10 h. Between 12 and 24 h following treatment, the amount of GAST1 RNA begins to decline and at 48 h the level is nearly equivalent to that of water-treated control plants. Nuclear runoff analysis indicates that 8 h after treatment with GA3, transcription of the GAST1 gene has increased only threefold, suggesting that GA acts both transcriptionally and post-transcriptionally. ABA partially inhibits the GA-mediated increase in GAST1 RNA abundance while ethephon, kinetin, and 2,4-D have little effect. GAST1 RNA is detectable in untreated leaves, stems, petioles and flowers, but not in roots. The GAST1 gene encodes a 0.7 kb transcript. The sequence of the GAST1 cDNA and genomic clones indicates that the gene is interrupted by three introns and potentially encodes a 112 amino acid protein of unknown function.
authors.affiliation: Department of Plant Biology and Plant Molecular Genetics Institute, University of Minnesota, St Paul 55108.
authors.forename: L
authors.initials: L
authors.lastname: Shi
authors.forename: R T
authors.initials: RT
authors.lastname: Gast
authors.forename: M
authors.initials: M
authors.lastname: Gopalraj
authors.forename: N E
authors.initials: NE
authors.lastname: Olszewski
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000595:Amino Acid Sequence; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D005638:Fruit / Q000235:genetics*; D017343:Genes, Plant / Q000235:genetics*; D005875:Gibberellins / Q000494:pharmacology; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014018:Tissue Distribution; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: C081148:GAST1 protein, Lycopersicon esculentum; D005875:Gibberellins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D000040:Abscisic Acid; C007842:gibberellic acid