Clock gene expression profiles in TOC1 mis-expressed lines. A: The simulated profiles of LHY/CCA1 mRNA under constant light conditions are shown for wild type (wt), toc1 and TOC1-ox lines by black solid, dashed and grey lines, respectively. TOC1-ox was simulated with n16 = 0.1. Simulations were run after entrainment of the clock to 12 L:12D conditions to match the data. B: Experimental data for LHY mRNA in wild type and toc1 plants under constant light conditions are redrawn from ; C: Cartoon illustrating the clock gene profiles in TOC1 mis-expressed lines relative to the wild type. Coloured lines represent the expression of LHY and its inhibitors PRR9, PRR7, PRR5, TOC1, as shown in the legend for the wild type. Blue connections on the wild-type panel (left) show the inhibition of PRR9, PRR7, PRR5 by TOC1. The release of this inhibition in the toc1 mutant (centre) results in the increase in PRR expression, which causes the reduction of the LHY amplitude and, together with the absence of TOC1, shortens the clock period in the toc1 mutant. On the contrary, overexpression of TOC1 (right) reduces PRR expression and allows LHY levels to rise in the morning, while higher TOC1 delays LHY at the end of the night, lengthening the period in TOC1-ox.
Pokhilko et al. BMC Systems Biology 2013 7:23 doi:10.1186/1752-0509-7-23