Expression data from gbf1, gbf1 hy5, and gbf1 hyh mutants

Three bZIP transcription factors (TFs), namely GBF1, HY5, and HYH, form heterodimers with each other and regulate photomorphogenesis in an interdependent manner. GBF1 acts as both a positive and negative regulator of photomorphogenesis, whereas HY5 and HYH mainly act as positive regulators of photomorphogenesis. To study the effect of HY5 and HYH on GBF1-mediated genome-wide expression, transcript profiling was performed in the gbf1 single mutant and gbf1hy5 and gbf1hyh double mutants. Our study revealed that GBF1 mainly acts antagonistic to HY5 and HYH for genome-wide expression. Four-day-old constant white-light grown Arabidipsis seedlings of wild-type (Col-0), gbf1 mutant, gbf1 hy5 double mutant and gbf1 hyh double mutant were harvested for total RNA extraction and Affymetrix microarray hybridisation. Two biological replicates of each sample were used for hybridisation and data analysis. Data were analysed using GeneSpring software by utilising the RMA algorithm. To draw the conclusions from this study, probe level intensity of gbf1, gbf1 hy5, and gbf1 hyh was normalised against the probe level intensity of wild-type, and also the probe level intensity of gbf1 hy5 and gbf1 hyh double mutants was normalised against the probe level intensity of the gbf1 single mutant.