Quantitative analysis of regulatory flexibility under changing environmental conditions

Kieron D. Edwards, Ozgur E. Akman, Kirsten Knox, Peter J. Lumsden, Adrian W. Thomson, Paul E. Brown, Alexandra Pokhilko, Laszlo Kozma-Bognar, Ferenc Nagy, David A. Rand, Andrew J. Millar

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70 Citations (Scopus)

Abstract

The circadian clock controls 24-h rhythms in many biological processes, allowing appropriate timing of biological rhythms relative to dawn and dusk. Known clock circuits include multiple, interlocked feedback loops. Theory suggested that multiple loops contribute the flexibility for molecular rhythms to track multiple phases of the external cycle. Clear dawn-and dusk-tracking rhythms illustrate the flexibility of timing in Ipomoea nil. Molecular clock components in Arabidopsis thaliana showed complex, photoperiod-dependent regulation, which was analysed by comparison with three contrasting models. A simple, quantitative measure, Dusk Sensitivity, was introduced to compare the behaviour of clock models with varying loop complexity. Evening-expressed clock genes showed photoperiod-dependent dusk sensitivity, as predicted by the three-loop model, whereas the one-and two-loop models tracked dawn and dusk, respectively. Output genes for starch degradation achieved dusk-tracking expression through light regulation, rather than a dusk-tracking rhythm. Model analysis predicted which biochemical processes could be manipulated to extend dusk tracking. Our results reveal how an operating principle of biological regulators applies specifically to the plant circadian clock. Molecular Systems Biology 6: 424; published online 2 November 2010; doi:10.1038/msb.2010.81

Original languageEnglish
Article number424
Number of pages11
JournalMolecular Systems Biology
Volume6
DOIs
Publication statusPublished - Nov 2010

Keywords

  • Arabidopsis thaliana
  • biological clocks
  • dynamical systems
  • gene regulatory networks
  • mathematical models
  • photoperiodism
  • arabidopsis circadian clock
  • gene-expression
  • temperature-compensation
  • flowering response
  • starch metabolism
  • time measurement
  • semidian rhythm
  • pharabitis-nil
  • key pathways
  • transcription

Cite this

Edwards, K. D., Akman, O. E., Knox, K., Lumsden, P. J., Thomson, A. W., Brown, P. E., Pokhilko, A., Kozma-Bognar, L., Nagy, F., Rand, D. A., & Millar, A. J. (2010). Quantitative analysis of regulatory flexibility under changing environmental conditions. Molecular Systems Biology, 6, [424]. https://doi.org/10.1038/msb.2010.81