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. 2003 Jun;132(2):732-8.
doi: 10.1104/pp.103.022343.

The circadian clock. A plant's best friend in a spinning world

Maria E Eriksson  1 , Andrew J Millar
Affiliations

The circadian clock. A plant's best friend in a spinning world

Maria E Eriksson et al. Plant Physiol. 2003 Jun.
No abstract available

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Figures

Figure 1.
Figure 1.
A current view of the circadian system in Arabidopsis. Proteins are encircled, proteins that are unlikely to function in the core timing loop have smaller symbols, and genes are shown in rectangles. CCA1 and LHY are expressed in the early day; their respective proteins repress TOC1 transcription (bold line). CCA1/LHY proteins decay at the end of the day, derepressing TOC1 transcription. The accumulation of TOC1, ELF3, ELF4, and GI proteins during the night activates the transcription of CCA1/LHY the next morning by an unknown mechanism (light arrow). Interactions between TOC1 and PIL1/PIF3 proteins may occur at the CCA1 and LHY promoters, enhancing their expression in a light-dependent fashion. APRR9 transcription is light activated (flash); it is the first gene to be expressed in the APRR/TOC1 quintet, followed by APRR7, APRR5, APRR3, and TOC1. TOC1 can repress APRR9 RNA expression; otherwise, it is not very clear how the protein quintet interact. Components that have not been located relative to the loops shown here are omitted (e.g. TEJ and the ZTL family).
Figure 2.
Figure 2.
Photoperiodic control of flowering. The detection of day length through the circadian system is dependent on light signals perceived through the photoreceptors cry2 and phyA, integrated at the level of CO expression. When and only when CO is expressed at high levels in the light phase, expression of the FT gene is induced. FT activates downstream flowering genes, committing the plant to the flowering state. Dark bars indicate the dark hours and yellow bars indicate the light hours of the light/dark cycle. The flash indicates light perceived, and the dotted arrow indicates the light-activated CO signal that activates FT expression.
See this image and copyright information in PMC

References

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