イネにおけるジベレリン受容と信号伝達

概要

論文の詳細を見る
Gibberellins (GAs) are phytohormones that are essential for many developmental processes in plants. Recent molecular biological and genetical studies have identified several positive and negative regulators of GA signalling pathways in higher plants. Among them, the DELLA protein has been considered one of the most important factors, which functions as a negative regulator of GA signalling; its degradation through the ubiquitin/proteasome pathway is a key event in the regulation of GA-stimulated processes. Recently, we isolated a G__-A i__-nsensitive d__-warf mutant of rice, gidl. The GID1 encodes an unknown protein with similarity to the hormone sensitive lipases (HSL) and the GID1-GFP signal was observed preferentially in nuclei. Recombinant GST-GID1 had a high affinity only for bioactive GAs, while mutated GST-GID1 corresponding three gidl alleles, had no GA-binding affinity. The K_d value for GA_4 was estimated to be around 10^<-7>M, enough to account for the GA dependency on shoot elongation. Moreover, GID1 bound to SLR1, a rice DELLA protein, in a GA dependent manner in yeast cells. GID1 overexpression resulted in a GA-hypersensitive phenotype. Taken together, these results indicate that GID1 is a soluble receptor mediating GA signaling in rice.
植物化学調節学会の論文
2005-10-13