Disease relevance of DET2

• The chi2 mature plants exhibited phenotypic features such as dwarfism, reduced male fertility and dark green, rounded epinastic leaves, which are characteristics of brassinosteroid-deficient mutants such as det2, cpd, and dwf4 [1].

High impact information on DET2

• The Arabidopsis DET2 gene encodes a protein that shares significant sequence identity with mammalian steroid 5 alpha-reductases [2].
• We show that DET2 actually acts at the second step in brassinolide biosynthesis in the 5 alpha-reduction of (24R)-24-methylcholest-4-en-3-one, which is further modified to form campestanol [3].
• Arabidopsis det2 mutants are small dark-green dwarfs displaying pleiotropic defects in light-regulated development during multiple stages of the plant life cycle [4].
• BR-regulated genes generally responded more potently in the det2 mutant than in the WT, and they showed only limited response in a BR-insensitive mutant, bri1 [5].
• Both show a mild phenotype in comparison with BR-deficient mutants such as cpd/cbb3, det2, and dwf4 [6].

Biological context of DET2

• Using a cDNA array, we identified genes that respond to BR in the det2 suspension culture of Arabidopsis, and found that epi-brassinolide upregulated transcription of the CycD3, a D-type plant cyclin gene through which cytokinin activates cell division [7].

Anatomical context of DET2

• When expressed in mammalian cells (COS-7), recombinant LeDET2 was active on substrates typical of mammalian 5alphaRs (progesterone, testosterone, androstenedione), but reduced at very low levels campestenone, the substrate described for AtDET2 [8].

Associations of DET2 with chemical compounds

• The results of these studies indicate the early operating steps of BR biosynthesis as: campesterol --> 4-en-3beta-ol --> 4-en-3-one --> 3-one --> campestanol in Arabidopsis, with det2 deficient in the conversion of 4-en-3-one to 3-one [9].
• We have undertaken metabolic experiments with 2H-labeled substrates of intermediates involved in the formation of campestanol from campesterol, and quantitative analysis of intermediates in Arabidopsis wild type and det2 [9].
• Similar results were obtained with the expression in COS-7 of recombinant AtDET2 that showed 5alphaR activity for progesterone and not for campestenone [8].

Analytical, diagnostic and therapeutic context of DET2

• With the use of DNA microarray analysis, we identified BR-regulated genes in the wild type (WT; Columbia) of Arabidopsis and in the BR-deficient mutant, det2 [5].
• Here, we used biochemical measurements and biological assays to determine the precise biochemical defect in det2 mutants [3].

References