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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.