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Cloning of the Arabidopsis ent-kaurene oxidase gene GA3.

ABSTRACT: The ga3 mutant of Arabidopsis is a gibberellin-responsive dwarf. We present data showing that the ga3-1 mutant is deficient in ent-kaurene oxidase activity, the first cytochrome P450-mediated step in the gibberellin biosynthetic pathway. By using a combination of conventional map-based cloning and random sequencing we identified a putative cytochrome P450 gene mapping to the same location as GA3. Relative to the progenitor line, two ga3 mutant alleles contained single base changes generating in-frame stop codons in the predicted amino acid sequence of the P450. A genomic clone spanning the P450 locus complemented the ga3-2 mutant. The deduced GA3 protein defines an additional class of cytochrome P450 enzymes. The GA3 gene was expressed in all tissues examined, RNA abundance being highest in inflorescence tissue.

SUBMITTER: Helliwell CA

PROVIDER: S-EPMC21195 | biostudies-literature | 1998 Jul

REPOSITORIES: biostudies-literature

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Cloning of the Arabidopsis ent-kaurene oxidase gene GA3.

Helliwell C A CA Sheldon C C CC Olive M R MR Walker A R AR Zeevaart J A JA Peacock W J WJ Dennis E S ES

Proceedings of the National Academy of Sciences of the United States of America 19980701 15

The ga3 mutant of Arabidopsis is a gibberellin-responsive dwarf. We present data showing that the ga3-1 mutant is deficient in ent-kaurene oxidase activity, the first cytochrome P450-mediated step in the gibberellin biosynthetic pathway. By using a combination of conventional map-based cloning and random sequencing we identified a putative cytochrome P450 gene mapping to the same location as GA3. Relative to the progenitor line, two ga3 mutant alleles contained single base changes generating in- ...[more]

PMID: 9671797

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