The photomorphogenesis regulator DET1 binds the amino-terminal tail of histone H2B in a nucleosome context.
Light provides a major source of information from the environment during plant growth and development. Recent results suggest that the key events controlling light-regulated gene expression in plants are translocation of the phytochrome photoreceptors into the nucleus, followed by their binding to transcription factors such as PIF3. Coupled with this, the degradation of positively acting intermediates such as the transcription factor HY5 by COP1 and the COP9 signalosome appears to be an important process whereby photomorphogenesis is repressed in darkness (e.g., ). Genetic analyses in Arabidopsis and tomato have revealed that the nuclear protein DET1 also plays a key role in the repression of photomorphogenesis. However, the function of this protein has remained a mystery. In a series of in vitro experiments, we provide persuasive evidence that DET1 binds to nonacetylated amino-terminal tails of the core histone H2B in the context of the nucleosome. Furthermore, we have utilized FRET (fluorescence resonance energy transfer) imaging with GFP variants to demonstrate this interaction within the nucleus of living plant cells. Given the dramatic photomorphogenic phenotypes of det1 mutants, we propose that chromatin remodeling plays a heretofore unsuspected role in regulating gene expression during photomorphogenesis.
Benvenuto
Giovanna
G
Laboratory of Molecular Plant Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, I-80121 Naples, Italy.
Formiggini
Fabio
F
Laflamme
Pierre
P
Malakhov
Mikhail
M
Bowler
Chris
C
D000107:Acetylation; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D002843:Chromatin / Q000378:metabolism / Q000648:ultrastructure; D031541:Fluorescence Resonance Energy Transfer; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D018551:Solanum lycopersicum / Q000378:metabolism* / Q000528:radiation effects; D009024:Morphogenesis / Q000528:radiation effects; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D009707:Nucleosomes / Q000378:metabolism*; D010641:Phenotype; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017384:Sequence Deletion
D029681:Arabidopsis Proteins; D002843:Chromatin; C088435:DET1 protein, Arabidopsis; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D009707:Nucleosomes; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins