| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
In the current research, we studied the receptors carrying the extracellular leucine-rich-repeat (LRR)-domain. This domain has the ability to bind its ligand. In plants and animals, these receptors play an important role in cellular mechanisms involved in the growth, development and defense. Therefore, to elucidate these mechanisms, it is important to characterize the interactions between the extracellular LRR-domain and its ligand biochemically. To conduct the biochemical characterization of these interactions, we developed the system to functionally express these extracellular LRR-domains in Escherichia coli.
Using this system, we characterized the tomato receptor tBRI1/SR160. This receptor has the ability to recognize two different kinds of ligand molecules, the steroid hormone brassinolide and the polypeptide hormone systemin. Brassinolide promotes plant growth and systemin induces the expression of plant defensive genes. We investigated how this receptor recognizes two different kinds of ligand molecules. First we expressed its entire extracellular LRR-domain in. Escherichia coli and confirmed its ability to bind brassinolide. Interestingly, the excess molar of systemin did not compete this binding. This showed the tBRI1/SR160 has the two different ligand-binding domains, the brassinolide-binding domain and the systemin-binding domain. This is a novel mechanisms in the ligand-recognition of LRR-containing receptors.
Furthermore, during the course of this research, we developed an efficient system to clone the multiple DNA fragments into the vector.
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