Abstract
In germinated cereal aleurone, gibberellins induce gene-expression for hydrolytic enzymes to mobilize stored molecules. Functions of GA-primary genes, such as GAMyb, act key roles leading to this regulation. To dissect true mechanism of GA-mediated gene-expression, regulation of primary gene-expression themselves have been studied. Previous analyses indicated that enhancer activities present in a large intron should confer GA-response of primary genes, showing a similarity with known-genes regulated by chromatin organization. Following a hypothesis that chromatin-based control would be important for initial GA-actions, DNA methylation of GAMyb has been evaluated. Bisulfite sequencing revealed limited DNA methylation in the promoter region. Methylation-level of seedling was higher than that in aleurone. Asymmetric-type of methylation appeared to partially reduce with treatment of GA. Total extent of DNA methylation showed a correlation with differences between embryo and endosperm nuclear-types, implying that polyploidy of endosperm aleurone tissues should contribute high-response to GA.
