Molecular interaction between COP1 and HY5 defines a regulatory switch for light control of Arabidopsis development.
Arabidopsis COP1 acts as a light-inactivable repressor of photomorphogenic development, but its molecular mode of action remains unclear. Here, we show that COP1 negatively regulates HY5, a bZIP protein and a positive regulator of photomorphogenic development. Both in vitro and in vivo assays indicate that COP1 interacts directly and specifically with HY5. The hyperphotomorphogenic phenotype caused by the over-expression of a mutant HY5, which lacks the COP1-interactive domain, supports the regulatory role of HY5-COP1 interaction. Further, HY5 is capable of directly interacting with the CHS1 minimal promoter and is essential for its light activation. We propose that the direct interaction with and regulation of transcription factors by COP1 may represent the molecular mechanism for its control of gene expression and photomorphogenic development.
Ang
L H
LH
Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA.
Chattopadhyay
S
S
Wei
N
N
Oyama
T
T
Okada
K
K
Batschauer
A
A
Deng
X W
XW
D000217:Acyltransferases / Q000235:genetics; D000818:Animals; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D019281:Dimerization; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D008027:Light; D009687:Nuclear Proteins / Q000378:metabolism; D010455:Peptides; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000201:enzymology / Q000254:growth & development; D011401:Promoter Regions, Genetic / Q000502:physiology; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C082750:H5 protein, synthetic; D009687:Nuclear Proteins; D010455:Peptides; D010940:Plant Proteins; D011506:Proteins; D012097:Repressor Proteins; D000217:Acyltransferases; C020141:flavanone synthetase; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases