Robust and flexible response of the Ostreococcus tauri circadian clock to light/dark cycles of varying photoperiod.
The green microscopic alga Ostreococcus tauri has recently emerged as a promising model for understanding how circadian clocks, which drive the daily biological rhythms of many organisms, synchronize to the day/night cycle in changing weather and seasons. Here, we analyze translational reporter time series data for the central clock genes CCA1 and TOC1 for a wide range of daylight durations (photoperiods). The variation of temporal expression profiles with day duration is complex, with the two protein peaks tracking different times of the day. Nevertheless, all profiles are accurately reproduced by a simple two-gene transcriptional loop model whose parameters depend on light only through the photoperiod value. We show that this non-intuitive behavior allows the circadian clock to combine flexibility and robustness with respect to daylight fluctuations.
Laboratoire de Physique des Lasers, Atomes, et Molécules, Université Lille 1, CNRS, Unité Mixte de Recherche 8523, Unité de Formation et de Recherche de Physique, Villeneuve d'Ascq, France.
Quentin
Q
Thommen
Benjamin
B
Pfeuty
Florence
F
Corellou
François-Yves
FY
Bouget
Marc
M
Lefranc
D020418:Algal Proteins / Q000378:metabolism*; D000460:Chlorophyta / Q000502:physiology*; D057906:Circadian Clocks / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D008027:Light; D008954:Models, Biological; D017440:Photoperiod; D012621:Seasons; D014157:Transcription Factors / Q000378:metabolism*
D020418:Algal Proteins; D014157:Transcription Factors