| Project/Area Number |
11640660
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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
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| Research Institution | Akita Prefectural University |
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Principal Investigator |
ONO Michiyuki Faculty of Bioresource Sciences, Akita Prefectural University, Associate Professor, 生物資源科学部, 助教授 (50201405)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAGI Nobuaki Faculty of Bioresource Sciences, Akita Prefectural University, Post-doctoral fellow, 生物資源科学部, 流動研究員
UEDA Kenji Faculty of Bioresource Sciences, Akita Prefectural University, Assistant Professor, 生物資源科学部, 助手 (80279504)
INOUE Masayasu Faculty of Bioresource Sciences, Akita Prefectural University, Professor, 生物資源科学部, 教授 (90176446)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1999: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Arabidopsis thaliana / circadian rhythm / davlength / floral induction / flower induction / germin-like protein / Pharbitis nil / photoperiodism |
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| Research Abstract |
To clarify the molecular basis of the photoperiodic induction of flowering, we studied the differences in gene expression in short-day induced cotyledons of Pharbitis nil cv.Violet. We identified a gene whose transcript is accumulated in leaves and cotyledons during the flower-inductive dark period, and designated PnGLP(P.nil germin-like protein). PnGLP is a member of the leaf-type subfamily of Germin and GLP genes. Northern analysis revealed that the level of PnGLP mRNA showed a circadian rhythm, with maxima around ZT10(10 h after the beginning of the dark period), and this oscillation continued in lengthened continuous darkness. This pattern of expression showed an antiphase against CAB(chlorophyll a/b-binding protein) that is of the most widely studied gene. To study the molecular mechanisms of leaf-type GLP gene regulation in relation to photoperiodism, homologues of PnGLP in Arabidopsis(a long-day plant), namely, AtGLP1 and AtGLP2 were isolated and characterized. Accumulation of AtGLP1 and AtGLP2 mRNA in leaf also showed circadian rhythms, with maxima around ZT14(14 h after the beginning of the light period). This oscillation continued mostly under continuous light. Thus, the mode of regulation in AtGLP1 and AtGLP2 showed opposite to that of PnGLP, possibly reflecting the physiological differences between short-day plants and long-day plants. We analyzed promoter region of these genes by means of determination of nucleotide sequence and functional analysis using a luciferase gene as a reporter. We did not find any conserved cis-elements among there promoters, but observed several GATA elements in all the three promoters. In case of AtGLP2 promoter, we found two GATA elements that may responsible to the circadian expression under the continuous light. We speculated that there are several GATA-binding proteins that govern expression of clock-controlled genes at specific timings during circadian time. Our experiment is currently underway on such hypothesis.
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