Isolation and expression of three gibberellin 20-oxidase cDNA clones from Arabidopsis.
AUTOR(ES)
Phillips, A L
RESUMO
Using degenerate oligonucleotide primers based on a pumpkin (Cucurbita maxima) gibberellin (GA) 20-oxidase sequence, six different fragments of dioxygenase genes were amplified by polymerase chain reaction from arabidopsis thaliana genomic DNA. One of these was used to isolate two different full-length cDNA clones, At2301 and At2353, from shoots of the GA-deficient Arabidopsis mutant ga1-2. A third, related clone, YAP169, was identified in the Database of Expressed Sequence Tags. The cDNA clones were expressed in Escherichia coli as fusion proteins, each of which oxidized GA12 at C-20 to GA15, GA24, and the C19 compound GA9, a precursor of bioactive GAs; the C20 tricarboxylic acid compound GA25 was formed as a minor product. The expression products also oxidized the 13-hydroxylated substrate GA53, but less effectively than GA12. The three cDNAs hybridized to mRNA species with tissue-specific patterns of accumulation, with At2301 being expressed in stems and inflorescences, At2353 in inflorescences and developing siliques, and YAP169 in siliques only. In the floral shoots of the ga1-2 mutant, transcript levels corresponding to each cDNA decreased dramatically after GA3 application, suggesting that GA biosynthesis may be controlled, at least in part, through down-regulation of the expression of the 20-oxidase genes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=157456Documentos Relacionados
- Overexpression of 20-Oxidase Confers a Gibberellin-Overproduction Phenotype in Arabidopsis
- Seed and Hormonal Regulation of Gibberellin 20-Oxidase Expression in Pea Pericarp.
- Molecular cloning and photoperiod-regulated expression of gibberellin 20-oxidase from the long-day plant spinach.
- The Involvement of Gibberellin 20-Oxidase Genes in Phytochrome-Regulated Petiole Elongation of Arabidopsis
- Biotin synthase from Arabidopsis thaliana. cDNA isolation and characterization of gene expression.