GAMYB controls different sets of genes and is differentially regulated by microRNA in aleurone cells and anthers
GAMYB is a component of gibberellin (GA) signaling in cereal aleurone cells, and has an important role in flower development. However, it is unclear how GAMYB function is regulated. We examined the involvement of a microRNA, miR159, in the regulation of GAMYB expression in cereal aleurone cells and flower development. In aleurone cells, no miR159 expression was observed with or without GA treatment, suggesting that miR159 is not involved in the regulation of GAMYB and GAMYB-like genes in this tissue. miR159 was expressed in tissues other than aleurone, and miR159 over-expressors showed similar but more severe phenotypes than the gamyb mutant. GAMYB and GAMYB-like genes are co-expressed with miR159 in anthers, and the mRNA levels for GAMYB and GAMYB-like genes are negatively correlated with miR159 levels during anther development. Thus, OsGAMYB and OsGAMYB-like genes are regulated by miR159 in flowers. A microarray analysis revealed that OsGAMYB and its upstream regulator SLR1 are involved in the regulation of almost all GA-mediated gene expression in rice aleurone cells. Moreover, different sets of genes are regulated by GAMYB in aleurone cells and anthers. GAMYB binds directly to promoter regions of its target genes in anthers as well as aleurone cells. Based on these observations, we suggest that the regulation of GAMYB expression and GAMYB function are different in aleurone cells and flowers in rice.
Document Type: Research Article
Affiliations: 1: Bioscience and Biotechnology Center, Nagoya University, Furocho, Chikusa, Nagoya 464-8601, Japan, 2: Integrated Genomics Research Team, PSC, RIKEN, Suehirocho 1-7-22, Tsurumi, Yokohama 230-0045, Japan, 3: Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo, Tokyo 113-8657, Japan,
Publication date: August 1, 2006