Cloning of the Arabidopsis ent-kaurene oxidase gene GA3.
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.
Commonwealth Scientific and Industrial Research Organization, Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia.
C A
CA
Helliwell
C C
CC
Sheldon
M R
MR
Olive
A R
AR
Walker
J A
JA
Zeevaart
W J
WJ
Peacock
E S
ES
Dennis
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D004274:DNA, Recombinant; D005786:Gene Expression Regulation; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D010105:Oxygenases / Q000235:genetics*
D004274:DNA, Recombinant; D003577:Cytochrome P-450 Enzyme System; D010105:Oxygenases; C066398:ent-kaurene oxidase