High impact information on DET1

• DET1, a negative regulator of light-mediated development and gene expression in arabidopsis, encodes a novel nuclear-localized protein [1].
• One candidate for a signal transduction component that may integrate light with developmental pathways is the Arabidopsis DET1 gene product [1].
• An analysis of a number of det1 mutants indicates that mutants with partial DET1 activity develop as light-grown plants in the dark. det1 null mutants share this phenotype, but also display severe defects in temporal and spatial regulation of gene expression [1].
• COP10 is a ubiquitin-conjugating enzyme variant (UEV), which is thought to act together with COP1, DET1, and the COP9 signalosome (CSN) in Arabidopsis to repress photomorphogenesis [2].
• Purified CDD (COP10, DDB1, DET1) complex also shows enhancement of E2 activity (UEA) similar to that observed with COP10 itself [2].

Biological context of DET1

• GFP-DET1 rescues the det1 phenotype, is localized to the nucleus, and forms an approximately 350 kDa complex, which is required for full DET1 activity [3].
• DET1 encodes a nuclear protein that appears to act downstream from multiple photoreceptors to regulate morphogenesis and gene expression in response to light [3].
• CUL4 associates with DDB1 and DET1 and its downregulation affects diverse aspects of development in Arabidopsis thaliana [4].
• Epistasis studies suggest that DOC1 and DET3 act downstream from DET1 on two separate branches in the phototransduction pathway [5].
• The genome expression profiles of the viable mutants of COP1 and DET1 in darkness mimic those of the physiological light-regulated genome expression profiles, whereas the genome expression profiles of representative lethal mutants belong to another clade and significantly diverge from the normal light control of genome expression [6].

Anatomical context of DET1

• Thus, peroxisomes, whose functions are still largely unexplored, play a key role in a photomorphogenetic pathway negatively regulated by the DET1 and COP proteins [7].
• During plastid differentiation in leaves of dark-grown plants, DET1 is required for the action of ABI3 as it is during seed development [8].

Associations of DET1 with chemical compounds

• These results suggest an important role for cytokinins during greening of Arabidopsis, and may implicate abnormal cytokinin levels or an increased sensitivity to cytokinins as explanations for some of the observed phenotypes of det1 mutants [9].

Physical interactions of DET1

• Arabidopsis COP10 forms a complex with DDB1 and DET1 in vivo and enhances the activity of ubiquitin conjugating enzymes [2].
• The photomorphogenesis regulator DET1 binds the amino-terminal tail of histone H2B in a nucleosome context [10].

Regulatory relationships of DET1

• DET1 regulates the proteasomal degradation of LHY, a component of the Arabidopsis circadian clock [11].
• A model is proposed involving blue light, DET1 and phytochrome in regulating transcription from the psbD BLRP [12].

Other interactions of DET1

• Our data provide evidence that DET1, COP1, and COP9 most likely act as negative regulators of several sets of genes, not just those involved in light-regulated seedling development [13].
• This suggests that COP1 and DET1 work downstream of the UV-B signaling pathway [14].
• The daily onset of LHY gene expression was advanced by approximately 4 h in det1-1 mutant plants, suggesting that the wild-type DET1 protein might function to repress its transcription during the subjective night. lhy-1 det1-1 double mutants exhibited arrhythmic expression of the CAB gene in constant light, similar to the lhy-1 mutant parent [11].
• In this work Arabidopsis cullin 4 is shown to assemble with DDB1, RBX1, DET1 and DDB2 in vitro and in planta [4].
• During seed maturation, ABI3 required DET1 to achieve its full expression [8].

References