Projects per year
Abstract / Description of output
The circadian clock is a fundamental feature of eukaryotic gene regulation that is emerging as an exemplar genetic sub-network for systems biology. The circadian system in Arabidopsis plants is complex, in part due to its phototransduction pathways, which are themselves under circadian control. We therefore analysed two simpler experimental systems. Etiolated seedlings entrained by temperature cycles showed circadian rhythms in the expression of genes that are important for the clock mechanism, but only a restricted set of downstream target genes were rhythmic in microarray assays. Clock control of phototransduction pathways remained robust across a range of light inputs, despite the arrhythmic transcription of light-signalling genes. Circadian interactions with light signalling were then analysed using a single active photoreceptor. Phytochrome A (phyA) is expected to be the only active photoreceptor that can mediate far-red (FR) light input to the circadian clock. Surprisingly, rhythmic gene expression was profoundly altered under constant FR light, in a phyA-dependent manner, resulting in high expression of evening genes and low expression of morning genes. Dark intervals were required to allow high-amplitude rhythms across the transcriptome. Clock genes involved in this response were identified by mutant analysis, showing that the EARLY FLOWERING 4 gene is a likely target and mediator of the FR effects. Both experimental systems illustrate how profoundly the light input pathways affect the plant circadian clock, and provide strong experimental manipulations to understand critical steps in the plant clock mechanism.
Original language | English |
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Pages (from-to) | 480-491 |
Number of pages | 12 |
Journal | The Plant Journal |
Volume | 66 |
Issue number | 3 |
Early online date | 4 Mar 2011 |
DOIs | |
Publication status | Published - 31 May 2011 |
Keywords / Materials (for Non-textual outputs)
- Arabidopsis
- Arabidopsis Proteins
- Circadian Clocks
- DNA-Binding Proteins
- Gene Expression Profiling
- Gene Expression Regulation, Plant
- Photoperiod
- Phytochrome A
- Seedling
- Temperature
- Transcription Factors
- circadian rhythms
- biological clocks
- Arabidopsis thaliana
- far red light
- Phytochrome
- gene circuit
Fingerprint
Dive into the research topics of 'Light inputs shape the Arabidopsis circadian system'. Together they form a unique fingerprint.Projects
- 6 Finished
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Mulitple light input signals to the gene network of the circadian clock
12/03/07 → 11/09/10
Project: Research
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SynthSys; formerly CSBE: Centre for Systems Biology at Edinburgh
Millar, A., Beggs, J., Ghazal, P., Goryanin, I., Hillston, J., Plotkin, G., Tollervey, D., Walton, A. & Robertson, K.
8/01/07 → 31/12/12
Project: Research
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Datasets
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Circadian gene expression under different light treatments by transcriptome profiling on microarrays
Edwards, K. D. (Creator) & Millar, A. (Creator), University of Edinburgh, 2007
http://affymetrix.arabidopsis.info/narrays/experimentpage.pl?experimentid=196
Dataset
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Circadian Clock Experiments: rhythmic transcriptome of dark-grown, temperature-entrained seedlings
Hall, A. (Creator) & Millar, A. (Creator), University of Edinburgh, 2005
http://affymetrix.arabidopsis.info/narrays/experimentpage.pl?experimentid=2
Dataset