Department of Integrated Biosciences / Innovational Biology / Molecular mechanisms of metamorphosis, camouflage and telomere maintenance
1981: Graduated, Faculty of Science, The University of Tokyo
1986: Doctor of Science from The University of Tokyo
1986: Researcher, National Institute Health Japan
1989: Lecturer, Faculty of Science, The University of Tokyo
1992-1993: Researcher, Department of Zoology, University of Washington (Seattle, USA)
1995: Associate Professor, Graduate School of Science, The University of Tokyo
1999: Associate Professor, Graduate School of Frontier Sciences, The University of Tokyo
2005: Professor, Graduate School of Frontier Sciences, The University of Tokyo
Graduate School: Molecular Mechanisms of Adaptation, Bioscience Analytical Instruments
Others: Part-time Professor, University of the Air
1) Molecular mechanism of retrotransposition of LINE and its application
LINE occupy over 20% of the human genome and cause many genetic diseases, but retrotransposition mechanisms remain to be elucidated. We have studied telomere-specific LINE in insects and recently established the retrotransposition system with baculovirus-mediated gene delivery. Using this system, we continue to clarify the essential domains for LINE retrotransposition and retrotoransposition mechanisms. We are also applying this system to sequence-specific gene delivery and gene therapy vectors. (Ref. 1)
2) Creation of enzymes specifically cutting telomeric repeats
Telomere-specific LINE encodes the endonuclease, which specifically cuts insect telomeric repeats (TTAGG)n. We found that the enzyme domain expressed in E. coli cuts not only (TTAGG)n but also the human (TTAGGG)n, which is the only enzyme known to specifically cut the telomeric repeats. The anti-telomerase reagent and telomere length regulation is thought to be a potent repressor for ageing and tumorigenesis. We are analyzing cutting mechanisms of the telomere cutting enzyme in LINE, and attempting to apply it to the anti-tumor reagent. (Ref. 2)
3) Regulation of wing morphogenesis by steroid hormone in insects
Metamorphosis which is an adaptive developmental process controlled by hormones is observed in a wide variety of animals. We have been studying wing morphogenesis in Lepidoptera and found that the steroid hormone, ecdysone, induces cell proliferation in distal wing regions and cell death in proximal wing regions. This event is controlled by region-specific expression of ecdysone receptor (EcR) isoforms. It is thought that insects lack sexual hormones, but vertebrates have them. Males of the tussock moth, Orgyia recens, have wings, while female moths lose their wings, which is difference that appears during metamorphosis. We found that ecdysone induces wing degeneration in a female-specific manner. Wing morphogenesis and sexual dimorphism in Lepidoptera are good models to study steroid action during metamorphosis. (Refs. 3, 4)
4) Molecular mechanisms of camouflage marking patterns in insects
Variation of marking patterns on the body surfaces of animals is developed during evolution and is useful for the lifestyle and behavior of each animal. In particular, marking patterns in insects are often used in mimicry and camouflage for protecting them from predators. We are studying the molecular mechanisms for larval body markings and wing patterns, using the silkworm mutant strains and swallowtail butterflies, which change their marking patterns during larval development.
1) Takahashi, H. et al. EMBO.J. 21, 408-417, 2002.
2) Anzai, T. et al. Mol.Cell.Biol. 21, 100-108, 2001.
3) Fujiwara, H. and Ogai, S. Dev. Genes. Evol. 211, 118-123, 2001
4) Lobbia, S. et al. J. Insect Sci. 3, 1-7, 2003.
The Zoological Society of Japan
The Molecular Biology Society of Japan
The Japanese Society of Sericultural Sciences
Society of Evolutionary Studies, Japan
The Genetic Society of Japan
International Ecdysone Workshop Organizing Committee
2006.6-2007.5 Member of Reviewing Committee Japan Prize 2007
Department of Integrated Biosciences / / Evolutionary Developmental Biology
1990: Graduated, Faculty of Science, The University of Tokyo
1994: Research Associate, The University of Tokyo
1997: Doctor of Science from The University of Tokyo
2005 Associate Professor, The University of Tokyo
Graduate School:Molecular Mechanisms of Adaptation, Basic Biochemistry and Molecular Biology
Waseda University:Developmental Biology
To understand how the bodies of multicellular organisms are formed, I am studying the mechanism of the development of appendages such as legs and antennae at a molecular level in Drosophila. In addition, by comparing the process of Drosophila appendage formation with those of other insects at the molecular level, I am trying to understand the mechanism of how morphological variations are generated and how these variations have evolved.
1) Sakurai, K. T., Kojima, T., Aigaki, T. and Hayashi, S. (2007) "Differential control of cell affinity required for progression and refinement of cell boundary during Drosophila leg segmentation." Dev. Biol. 309, 126-136.
2) Tajiri, R., Tsuji, T., Ueda, R., Saigo, K. and Kojima, T. (2007) "Fate determination of Drosophila leg distal regions by trachealess and tango through repression and stimulation, respectively, of Bar homeobox gene expression in the future pretarsus and tarsus." Dev. Biol. 303, 461-473.
3) Yasunaga, K., Saigo, K. and Kojima, T. (2006) "Fate map of the distal portion of Drosophila proboscis as inferred from the expression and mutations of basic patterning genes." Mech. Dev. 123, 893-906.
4) Kozu, S., Tajiri, R., Tsuji, T., Michiue, T., Saigo, K. and Kojima, T. (2006) "Temporal regulation of late expression of Bar homeobox genes during Drosophila leg development by Spineless, a homolog of the mammalian dioxin receptor." Dev. Biol. 294, 497-508.
5) Kojima, T., Tsuji, T. and Saigo, K. (2005) "A concerted action of a paired-type homeobox gene, aristaless, and a homolog of Hox11/tlx homeobox gene, clawless, is essential for the distal tip development of the Drosophila leg." Dev. Biol. 279, 434-445.
6) Tsuji, T., Sato, A., Hiratani, I., Taira, M., Saigo, K. and Kojima, T. (2000). "Requirements of Lim1, a Drosophila LIM-homeobox gene, for normal leg and antennal development." Development 127, 4315-4323.
7) Kojima, T., Sato, M. and Saigo, K. (2000). "Formation and specification of distal leg segments in Drosophila by dual Bar homeobox gene, BarH1 and BarH2." Development 127, 769-778.
8) Kojima T. (2004). "The mechanism of Drosophila leg development along the proximodistal axis." Develop. Growth Differ. 46, 115-129.
Japanese Society of Developmental Biologists (JSDB)
Molecular Biology Society of Japan (MBSJ)
Japanese Drosophila Research Conference
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