Fig. 1

Inhibition of photosynthetic electron transport mimicked dark-repression-like genome-wide transcription profiles under illumination without dramatic loss of ATP content. a Temporal expression profiles of representative dark-repressed or -induced genes using three independent northern hybridisation analyses. We normalized the data for dark-repressed genes to the average value of illuminated samples (0, 30, and 60 minutes), while the data for dark-induced genes were normalized to the average value of dark-incubated samples (30 and 60 minutes). Bars indicate the standard deviation. b Organisation of Synechococcus expression profiles in the light, dark, and light with two inhibitors, DCMU and DBMIB. The data of all genes were normalized to the value at time 0 (minutes), corresponding to 12 hours in the light, and sorted by induction levels in the dark. c Total mRNA pools estimated from the sum of mRNA hybridisation signals normalized to genomic DNA signals under each condition. We normalized the signals at time 0 in the light to 1,000. Plots indicate the results from each independent experiment (n = 2). d The plot of PCA scores. Upper plot shows the PC1 score of each profile only. Filled circles and open circles indicate the samples at 30- and 60-minutes incubation, respectively. L 0 indicates scores of samples at time 0. For panels B to D, we used averaged data from two independent experiments. e Transition of the ATP level when photosynthetic activity was inhibited partially or completely. We transferred cells grown in the light for 12 hours to each condition at time 0. We normalized the ATP levels to the average value of control samples collected in the light at Time −10 to 0 (minutes). Bars indicate the standard deviation from triplicate cultures DBMIB 2,5-dibromo-3-methyl-6-isopropylbenzoquinone, DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea, PCA principal component analysis