Coordinated transcriptional regulation underlying the circadian clock in Arabidopsis

Abstract

In Arabidopsis thaliana, Early Flowering 4 (ELF4) is essential for maintenance of the circadian rhythm. Now three transcription factors are found that activate ELF4 during the day, but are negatively regulated at dawn to ensure cyclic ELF4 expression. The circadian clock controls many metabolic, developmental and physiological processes in a time-of-day-specific manner in both plants and animals1,2. The photoreceptors involved in the perception of light and entrainment of the circadian clock have been well characterized in plants3. However, how light signals are transduced from the photoreceptors to the central circadian oscillator, and how the rhythmic expression pattern of a clock gene is generated and maintained by diurnal light signals remain unclear. Here, we show that in Arabidopsis thaliana, FHY3, FAR1 and HY5, three positive regulators of the phytochrome A signalling pathway, directly bind to the promoter of ELF4, a proposed component of the central oscillator, and activate its expression during the day, whereas the circadian-controlled CCA1 and LHY proteins directly suppress ELF4 expression periodically at dawn through physical interactions with these transcription-promoting factors. Our findings provide evidence that a set of light- and circadian-regulated transcription factors act directly and coordinately at the ELF4 promoter to regulate its cyclic expression, and establish a potential molecular link connecting the environmental light–dark cycle to the central oscillator.

Cite this article

Li, G., Siddiqui, H., Teng, Y. et al. Coordinated transcriptional regulation underlying the circadian clock in Arabidopsis. Nat Cell Biol 13, 616–622 (2011). https://doi.org/10.1038/ncb2219

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