Arabidopsis thaliana Circadian Clock Is Regulated by the Small GTPase LIP1

Éva Kevei, Péter Gyula, Balázs Fehér, Réka Tóth, András Viczián, Stefan Kircher, Dean Rea, Dulguun Dorjgotov, Eberhard Schäfer, Andrew J. Millar, László Kozma-Bognár, Ferenc Nagy

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29 Citations (Scopus)

Abstract

Background: At the core of the eukaryotic circadian network, clock genes/proteins form multiple transcriptional/translational negative-feedback loops and generate a basic ∼24 hr oscillation, which provides daily regulation for a wide range of processes. This temporal organization enhances the fitness of the organism only if it corresponds to the natural day/night cycles. Light is the most effective signal in synchronizing the oscillator to environmental cycles. Results: The lip1-1 (light insensitive period 1) mutant isolated from the model plant Arabidopsis thaliana displays novel circadian phenotypes arising from specific defects in the light input pathway to the oscillator. In wild-type plants, period length shortens with increasing light fluence rates and the phase of rhythms can be shifted by light pulses administered to dark-adapted plants. In contrast, in lip1-1, period length is nearly insensitive to light intensity and significantly larger phase shifts (delays) can be induced during the subjective night. The mutant also displays elevated photomorphogenic responses to red and blue light, which cannot be explained by the circadian defect, suggesting distinct functions for LIP1 in the circadian light input and photomorphogenesis. The LIP1 gene encodes a functional, plant-specific atypical small GTPase, and therefore we postulate that it acts similarly to ZEITLUPE at postranscriptional level. Conclusions: LIP1 represents the first small GTPase implicated in the circadian system of plants. LIP1 plays a unique negative role in controlling circadian light input and is required for precise entrainment of the plant clock.

Original languageEnglish
Pages (from-to)1456-1464
Number of pages9
JournalCurrent Biology
Volume17
Issue number17
DOIs
Publication statusPublished - Sep 4 2007

Keywords

  • DEVBIO

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

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    Kevei, É., Gyula, P., Fehér, B., Tóth, R., Viczián, A., Kircher, S., Rea, D., Dorjgotov, D., Schäfer, E., Millar, A. J., Kozma-Bognár, L., & Nagy, F. (2007). Arabidopsis thaliana Circadian Clock Is Regulated by the Small GTPase LIP1. Current Biology, 17(17), 1456-1464. https://doi.org/10.1016/j.cub.2007.07.018