Figure 5.

Rhythmic expression of the luciferase gene (LUC) driven by the 1400 bp upstream fragment of the QH6 promoter in transgenic Arabidopsis thaliana Ler-0 and hy5-1 mutant lines. The steady-state level of LUC transcripts was quantified by real-time PCR, using Actin8 as a reference gene. Leaves were sampled in triplicate for two continuous days, with the first day in standard 12h/12h light/dark cycle and the second day in constant dark. ZT is Zeitgeber time and here represents time from light on at dawn. Filled and open bars indicate subjective days and nights. Data represent means ± SD. The differences of expression levels were assessed by unpaired Student's t-test. ^*p < 0.05 and ^**p < 0.01 in 1400::LUC transgenic Ler-0 vs. 1400::LUC transgenic hy5-1.