CIRCADIAN CLOCK ASSOCIATED1 and LATE ELONGATED HYPOCOTYL Function Synergistically in the Circadian Clock of Arabidopsis
Open Access
- 13 February 2009
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 150 (2), 834-843
- https://doi.org/10.1104/pp.108.133272
Abstract
The circadian clock is an endogenous mechanism that coordinates biological processes with daily and seasonal changes in the environment. Heterodimerization of central clock components is an important way of controlling clock function in several different circadian systems. CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY) are Myb-related proteins that function in or close to the central oscillator in Arabidopsis (Arabidopsis thaliana). Single mutants of cca1 and lhy have a phenotype of short-period rhythms. cca1 lhy double mutants show an even shorter period phenotype than the cca1 single mutant, suggesting that CCA1 and LHY are only partially functionally redundant. To determine whether CCA1 and LHY act in parallel or synergistically in the circadian clock, we examined their expression in both light-grown and etiolated seedlings. We have shown that LHY and CCA1 bind to the same region of the promoter of a Light-harvesting chlorophyll a/b protein (Lhcb, also known as CAB). CCA1 and LHY can form homodimers, and they also colocalize in the nucleus and heterodimerize in vitro and in vivo. In Arabidopsis, CCA1 and LHY physically interact in a manner independent of photoperiod. Moreover, results from gel filtration chromatography indicate that CCA1 and LHY are present in the same large complex in plants. Taken together, these results imply that CCA1 and LHY function synergistically in regulating circadian rhythms of Arabidopsis.Keywords
This publication has 59 references indexed in Scilit:
- Targeted Degradation of PSEUDO-RESPONSE REGULATOR5 by an SCFZTL Complex Regulates Clock Function and Photomorphogenesis in Arabidopsis thalianaPlant Cell, 2007
- TIME FOR COFFEEEncodes a Nuclear Regulator in theArabidopsis thalianaCircadian ClockPlant Cell, 2007
- ELF4Is Required for Oscillatory Properties of the Circadian ClockPlant Physiology, 2007
- The Molecular Basis of Temperature Compensation in the Arabidopsis Circadian ClockPlant Cell, 2006
- LUX ARRHYTHMO encodes a Myb domain protein essential for circadian rhythmsProceedings of the National Academy of Sciences of the United States of America, 2005
- Extension of a genetic network model by iterative experimentation and mathematical analysisMolecular Systems Biology, 2005
- The ELF4 gene controls circadian rhythms and flowering time in Arabidopsis thalianaNature, 2002
- Coordination of circadian timing in mammalsNature, 2002
- LHY and CCA1 Are Partially Redundant Genes Required to Maintain Circadian Rhythms in ArabidopsisDevelopmental Cell, 2002
- Critical Role for CCA1 and LHY in Maintaining Circadian Rhythmicity in ArabidopsisCurrent Biology, 2002