Fig. 3.
BZR1 has dual roles in regulating BR biosynthesis and growth responses. (A) Hypocotyl lengths of seedlings grown in continuous light for 7 days on medium containing 0 or 10 nM BL. Col, wild type control for bzr1-1D, det2, and bes1-1 mutants. WS, wild type control for the bes1-D mutant. DWF4-ox, a transgenic line that overexpresses DWF4. (B) Real-time PCR analysis of expression of BR biosynthetic genes in the bzr1-1D mutant and wild type (WT) seedlings grown in the dark (upper) or light (lower panel), and after 3 hr BL treatment (+BL). Average and standard deviation of 3 experiments are shown. (C) Microarray analysis of BR regulated genes in det2, bzr1-1D, and wild type (WT) Arabidopsis. Y axis: ratio of expression between det2 and wild type; X axis: ratio of expression between bzr1-1D and wild type. Upper panel: early-BR-responsive genes; Lower panel: late-BR-responsive genes. Dots: BR-induced genes; crosses, BR-repressed genes. (D) Average number of BRREs in the promoter regions of genes that are up- (BR-up) or down- (BR-down) and early- or late-regulated by BR treatment. Dashed line, calculated probability of occurrence of the BRRE sequence in any 500 bp Arabidopsis intergenic sequence. Grey bar, average number of BRREs in the 500 bp upstream regions of all genes in the Arabidopsis genome.