Summary of Research Project Results under JSPS FY2003
"Research for the Future Program"

1.Research Institution The University of Tokyo
2.Research Area Life Sciences
3.Research Field Mechanisms of the Advanced Function in Insects and Proposal of New Insectech
4.Term of Project FY 1999 - FY 2003
5.Project Number 99L01202
6.Title of Project Study on Molecular Mechanisms of Insect Growth and Social Development and its Application

7.Project Leader
Name Institution,Department Title of Position
Hiroshi, Kataoka The University of Tokyo, Graduate School of Frontier Sciences Professor

8.Core Members

Names Institution,Department Title of Position
Tadao, Matsumoto The University of Tokyo, Graduate School of Arts and Sciences Professor
Takeo, Kubo The University of Tokyo, Graduate School of Science Professor
Haruhiko, Kubo The University of Tokyo, Graduate School of Frontier Sciences Asscciate Professor

9.Summary of Research Results

   During study how ecdystroidogenesis in the prothoracic glands regulated, we purified a novel prothoracicostatic factor from the pupal brains and identified it as myosuppressin. Myosuppressin regulated the ecdysteroidogenesis by reducing cAMP revel in the prothoracic glands. Moreover, we identified a novel cytochrome P450 gene which converted ketodiol to ketotriol via carbon-25 hydroxylation.
   To understand the wing morphogenesis controlled by ecdysteroid, we have established three model systems using different lepidopteran wings. In the first model, we identified the putative gene responsible for the silkworm wingless mutant fl which lost the ecdysteroid response only in the wing discs. Baculovirus-mediated knockdown assay showed that the novel anexin gene (Anxb13) is encoded in the fl locus. In the second model, we found that cell degeneration and cell proliferation in the pupal wings induced by ecdysteroid, are controlled through region specific expression of two different ecdysone receptors, EcR-A and EcR-B1. In the third model, the female specific wing degeneration of the tussock moth, we found that ecdysteroid and ecdysteroid-dependent transcription factor BrC is involved in the specific degeneration.
   In order to understand the mechanism of sociality in insects, we established the new experimental system to identify the caste specific genes in damp-wood termite Hodotermopsis sjostedti, using a combination of the differential display method and the artificial induction of the soldier differentiation by the application of JHA. The SOL1 gene was actually identified as soldier-specific gene expressed in mandibular glands. As it became clear that this gene belongs to the lipocalin family, which was known as ligand-binding protein and work function as pheromone-like substances in some cases, SOL1 is suggestd to be an important factor in the social interaction in termites. Moreover, we found that the JHA application downregulates the expression of Cytochrome P450. In addition, dynamic morphological changes can be observed during the soldier differentiation.

10.Key Words
(1)metamorphosis   (2)ecdysteroid   (3)wing formation
(4)sociality   (5)caste differentiation   (6)insect
(7)steroid   (8)molting   (9)postembryonic development