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.
Helliwell
C A
CA
Commonwealth Scientific and Industrial Research Organization, Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia.
Sheldon
C C
CC
Olive
M R
MR
Walker
A R
AR
Zeevaart
J A
JA
Peacock
W J
WJ
Dennis
E S
ES
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