Involvement of RSG and 14-3-3 Proteins in the Transcriptional Regulation of a GA Biosynthetic Gene

Autor: Yohsuke Takahashi, Jutarou Fukazawa, Sarahmi Ishida, Akane Matushita
Rok vydání: 2003
Předmět:
Zdroj: Journal of Plant Growth Regulation. 22:195-204
ISSN: 1435-8107
0721-7595
DOI: 10.1007/s00344-003-0035-6
Popis: Our study focused on the functional analysis of RSG, a tobacco transcriptional activator with a bZIP domain. Expression of a dominant-negative form of RSG severely inhibited the process of cell elongation in stems and reduced the endogenous amounts of GA1, which is the major active gibberellin (GA) in tobacco in transgenic plants. To investigate the function of RSG in the regulation of GA amounts, we identified a target gene of RSG. This gene encodes ent-kaurene oxidase in the GA biosynthetic pathway. These results indicate that RSG regulates plant morphology through the transcriptional control of a GA biosynthetic enzyme. We identified the 14-3-3 signaling proteins as RSG-binding partners. The 14-3-3 proteins, which constitute a highly conserved isoform of homo- and heterodimeric molecules, associate with a number of signaling molecules to regulate growth, apoptosis and cell cycle progression. The mutant version of RSG that could not bind to 14-3-3 proteins exhibited a higher transcriptional activity than wild-type RSG. Consistent with this observation, the mutant RSG that could not bind to 14-3-3 proteins was predominantly localized in the nucleus, whereas wild-type RSG was distributed throughout the cell. 14-3-3 proteins negatively modulate RSG, which is involved in the regulation of endogenous amounts of GAs by controlling its intracellular localization.
Databáze: OpenAIRE
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