RT Journal Article
SR Electronic
T1 Two Isoforms of NADPH:Cytochrome P450 Reductase in<em>Arabidopsis thaliana</em>
JF Plant Physiology
JO Plant Physiol.
FD American Society of Plant Biologists
SP 357
OP 367
DO 10.1104/pp.116.1.357
VO 116
IS 1
A1 Mizutani, Masaharu
A1 Ohta, Daisaku
YR 1998
UL http://www.plantphysiol.org/content/116/1/357.abstract
AB We have investigated two NADPH-cytochrome (Cyt) P450 reductase isoforms encoded by separate genes (AR1 and AR2) in Arabidopsis thaliana. We isolated AR1 and AR2 cDNAs using a mung bean (Phaseolus aureus L.) NADPH-Cyt P450 reductase cDNA as a probe. The recombinant AR1 and AR2 proteins produced using a baculovirus expression system showed similarK m values for Cyt c and NADPH, respectively. In the reconstitution system with a recombinant cinnamate 4-hydroxylase (CYP73A5), the recombinant AR1 and AR2 proteins gave the same level of cinnamate 4-hydroxylase activity (about 70 nmol min−1 nmol−1 P450). The AR2gene expression was transiently induced by 4- and 3-fold within 1 h of wounding and light treatments, respectively, and the induction time course preceded those of CYP73A5 and a phenylalanine ammonia-lyase (PAL1) gene. On the contrary, the AR1 expression level did not change during the treatments. Analysis of the AR1 andAR2 gene structure revealed that only theAR2 promoter contained three putative sequence motifs (boxes P, A, and L), which are involved in the coordinated expression of CYP73A5 and other phenylpropanoid pathway genes. These results suggest the possibility that AR2transcription may be functionally linked to the induced levels of phenylpropanoid pathway enzymes. GMgermination mediumP450Cyt P450P450 reductaseNADPH-Cyt P450 reductasePALPhe ammonia-lyase