| Project/Area Number |
15207006
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
植物生理・分子
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| Research Institution | The Graduate University for Advanced Studies (2004-2006)
Okazaki National Research Institutes (2003) |
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Principal Investigator |
WATANABE Masakatsu The Graduate University for Advanced Studies, School of Advanced Sciences, Professor, 先導科学研究科, 教授 (40124226)
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| Co-Investigator(Kenkyū-buntansha) |
KANDORI Hideki Nagoya Institute for Technology, School of Engeneering Sciences, Professor, 工学研究科, 教授 (70202033)
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| Project Period (FY) |
2003 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥48,880,000 (Direct Cost: ¥37,600,000、Indirect Cost: ¥11,280,000)
Fiscal Year 2006: ¥9,230,000 (Direct Cost: ¥7,100,000、Indirect Cost: ¥2,130,000)
Fiscal Year 2005: ¥11,830,000 (Direct Cost: ¥9,100,000、Indirect Cost: ¥2,730,000)
Fiscal Year 2004: ¥13,000,000 (Direct Cost: ¥10,000,000、Indirect Cost: ¥3,000,000)
Fiscal Year 2003: ¥14,820,000 (Direct Cost: ¥11,400,000、Indirect Cost: ¥3,420,000)
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| Keywords | blue-light sensor / photoactivated enzyme / cAMP / Euglena / photobehavior / PAC / flavin / 光運動反応 / 光センサー分子 / 青色光反応 / フラビン蛋白質 / 光活性化アデニル酸シクラーゼ / 青色光受容体 / FAD |
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| Research Abstract |
Photoactivated adenylyl cyclase (PAC) (Iseki et al. 2002 Nature) is a blue-light sensor protein responsible for photoavoidance behavior in a eukaryotic unicellular flagellate alga Euglena gracilis. It is composed of flavin-binding, light sensing domains and adenylyl cyclase catalytic domains so that it produces cAMP, a versatile intracellular second messenger, in response to blue-light irradiation.
By molecular phylogenetic analyses of homologues fo PAC in various euglenoids, it was suggested that PAC was introduced into Euglena almost concomitantly with the secondary symbiotic introduction of its chroloplasts (Koumura et al. 2004 Photochem Photobiol Sci).
By analyses of the photoactivation kinetics of purified PAC from Euglena, action spectrum and responsively to repeated short pulse irradiations were determined as well as intracellular cAMP concentration time courses. These results were in accordance with the corresponding in vivo photobehavior characteristics (Yoshikawa et al. 2005 Ph
… More
otochem Photobiol Sci).
By analyses of the photochemical cycle kinetics of a flavin-binding domain heterologously expressed in E. coil, threshold light flounce rate, quantum efficiency as well as half life of dark recovery ware determined which were in general similarity to other members of the so-called BLUF family of flavin-binding domains, mostly of prokaryotic origins (Ito et al. 2005 Photochem Photobiol Sci).
The unique distinguishing feature of PAC to act as a light sensor having intrinsic effector function of adenylyl cyclase provide promising possibilities to be used as a tool to photomanipulate various cAMP-dependent biological functions including neural and reproductive processes if it is successfully expressed functionally in heterologous systems (Iseki et al. 2002 Nature). This possibility was in fact realized by successful functional expression of PAC in frog oocytes, human cultured cells as well as in fly brains, particularly in which grooming behavior of the fly individual was specifically photosuppressed by external light irradiation (Schroeder-Lang 2007 Nature Methods). Less
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