PMID- 14617096
OWN - NLM
STAT- MEDLINE
DCOM- 20040504
LR  - 20240109
IS  - 0960-7412 (Print)
IS  - 0960-7412 (Linking)
VI  - 36
IP  - 3
DP  - 2003 Nov
TI  - A dwarf mutant strain of Pharbitis nil, Uzukobito (kobito), has defective 
      brassinosteroid biosynthesis.
PG  - 401-10
AB  - Japanese morning glory (Pharbitis nil) is a model plant characterized by a large 
      stock of spontaneous mutants. The recessive mutant Uzukobito shows strong 
      dwarfism with dark-green rugose leaves. The phenotype was rescued by the 
      application of brassinolide, a bioactive brassinosteroid (BR), indicating that 
      Uzukobito was a BR-deficient mutant. A detailed analysis of the endogenous BR 
      levels in Uzukobito and its parental wild-type plant showed that Uzukobito had a 
      lower level of BRs downstream of (24R)-24-methyl-5alpha-cholestan-3-one and (22S, 
      24R)-22-hydroxy-24-methyl-5alpha-cholestan-3-one than those in wild-type plants, 
      while their immediate precursors (24R)-24-methylcholest-4-en-3-one and (22S, 
      24R)-22-hydroxy-24-methylcholest-4-en-3-one accumulated relatively more in 
      Uzukobito. These results indicate that Uzukobito had a defect in the conversion 
      of (24R)-24-methylcholest-4-en-3-one and (22S, 
      24R)-22-hydroxy-24-methylcholest-4-en-3-one to their 5alpha-reduced forms, which 
      is catalyzed by de-etiolated2 (DET2) in Arabidopsis. The P. nil ortholog of the 
      DET2 gene (PnDET2) was cloned and shown to have the greatest similarity to DET2 
      among all the putative genes in Arabidopsis. Uzukobito had one amino acid 
      substitution from Glu62 to Val62 in the deduced amino acid sequence of PnDET2. 
      Recombinant PnDET2 expressed in COS-7 cells was found to be a functional steroid 
      5alpha-reductase (S5alphaR) converting (24R)-24-methylcholest-4-en-3-one to 
      (24R)-24-methyl-5alpha-cholestan-3-one, while PnDET2 with the mutation did not 
      show any catalytic activity. This shows that a plant S5alphaR can convert an 
      intrinsic substrate. All these results clearly demonstrate that the Uzukobito 
      phenotype resulted from a mutation on PnDET2, and a morphological mutant has been 
      characterized at the molecular level among a large stock of P. nil mutants.
FAU - Suzuki, Yoshihito
AU  - Suzuki Y
AD  - Department of Applied Biological Chemistry, The University of Tokyo, Bunkyo-ku, 
      Tokyo 113-8657, Japan. ayoshi@pgr1.ch.a.u-tokyo.ac.jp
FAU - Saso, Kazuyuki
AU  - Saso K
FAU - Fujioka, Shozo
AU  - Fujioka S
FAU - Yoshida, Shigeo
AU  - Yoshida S
FAU - Nitasaka, Eiji
AU  - Nitasaka E
FAU - Nagata, Shinji
AU  - Nagata S
FAU - Nagasawa, Hiromichi
AU  - Nagasawa H
FAU - Takatsuto, Suguru
AU  - Takatsuto S
FAU - Yamaguchi, Isomaro
AU  - Yamaguchi I
LA  - eng
SI  - GENBANK/AB106360
PT  - Journal Article
PL  - England
TA  - Plant J
JT  - The Plant journal : for cell and molecular biology
JID - 9207397
RN  - 0 (Plant Growth Regulators)
RN  - 0 (Plant Proteins)
RN  - 0 (Recombinant Proteins)
RN  - 0 (Steroids)
SB  - IM
MH  - Amino Acid Sequence
MH  - Animals
MH  - Base Sequence
MH  - COS Cells
MH  - Chlorocebus aethiops
MH  - Conserved Sequence
MH  - Genes, Plant
MH  - Genes, Recessive
MH  - Humans
MH  - Molecular Sequence Data
MH  - *Mutation
MH  - Phylogeny
MH  - Plant Growth Regulators/biosynthesis/*genetics
MH  - Plant Proteins/chemistry/*genetics
MH  - Recombinant Proteins/chemistry/metabolism
MH  - Sequence Alignment
MH  - Sequence Homology, Amino Acid
MH  - Solanaceae/classification/*genetics/growth & development
MH  - Steroids/*metabolism
MH  - Transfection
EDAT- 2003/11/18 05:00
MHDA- 2004/05/05 05:00
CRDT- 2003/11/18 05:00
PHST- 2003/11/18 05:00 [pubmed]
PHST- 2004/05/05 05:00 [medline]
PHST- 2003/11/18 05:00 [entrez]
AID - 1887 [pii]
AID - 10.1046/j.1365-313x.2003.01887.x [doi]
PST - ppublish
SO  - Plant J. 2003 Nov;36(3):401-10. doi: 10.1046/j.1365-313x.2003.01887.x.