The Transcriptional Network in the Arabidopsis Circadian Clock System

Abstract

The circadian clock is the biological timekeeping system that governs the approximately 24-h rhythms of genetic, metabolic, physiological and behavioral processes in most organisms. This oscillation allows organisms to anticipate and adapt to day-night changes in the environment. Molecular studies have indicated that a transcription-translation feedback loop (TTFL), consisting of transcriptional repressors and activators, is essential for clock function in Arabidopsis thaliana (Arabidopsis). Omics studies using next-generation sequencers have further revealed that transcription factors in the TTFL directly regulate key genes implicated in clock-output pathways. In this review, the target genes of the Arabidopsis clock-associated transcription factors are summarized. The Arabidopsis clock transcriptional network is partly conserved among angiosperms. In addition, the clock-dependent transcriptional network structure is discussed in the context of plant behaviors for adapting to day-night cycles.

Keywords: arabidopsis; circadian clock; plant development; transcription factors; transcriptional network.

Figure 1

A model of the transcriptional network of the Arabidopsis circadian clock. The clock transcription–translation feedback loop (TTFL) regulates biological processes through regulating key genes (TTFL-targets). Interactions within the clock TTFL are not shown. ‘Time’ is the peak time for mRNA expression under 12 h light/12 h dark conditions in DIURNAL [105]. Other TTFL-targets are detailed in the text.