Plant Science

Location and Timing

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Science  02 Aug 2013:
Vol. 341, Issue 6145, pp. 436-437
DOI: 10.1126/science.341.6145.436-d

In plants, the circadian network coordinates physiological processes with the daily rhythms of light and dark. The protein GIGANTEA (GI) is found in both nuclear and cytoplasmic compartments of the plant cell and regulates different partners in the two locations. Using Arabidopsis, Kim et al. constructed plants with disrupted subcellular localizations of GI. Their modeling analyses of the mutant plants show that GI in the nucleus acts as a positive regulator of the core oscillator gene LATE ELONGTED HYPOCOTYL (LHY), whereas GI in the cytoplasm acts as a negative regulator. This regulatory cycle supports a peak of LHY in the morning and a shift to the control of flowering genes by GI in the evening. The spatial segregation and opposition of function make the circadian system more robust in the face of stochastic noise; the models suggest that using one component in opposing ways generates a more stable system than does using two separate components.

Dev. Cell 26, 1016/j.devcell.2013.06.006 (2013).

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