| Project/Area Number |
15370019
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Saitama University (2004-2005)
The University of Tokyo (2003) |
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Principal Investigator |
OHMORI Masayuki Saitama University, Faculty of Science, Professor, 理学部, 教授 (80013580)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥12,500,000 (Direct Cost: ¥12,500,000)
Fiscal Year 2005: ¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2004: ¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2003: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | cyanobacteria / cAMP receptor protein / signal transduction / microarray / heterocyst / desiccation tolerance / nitrogen fixation / gene / ラン藻 / cAMP / 光受容タンパク質 / Anabaena / CRP / ゲルモビリティーシフト / 立体構造 / 乾燥ストレス / 遠赤色光 / トレハロース / 塩ストレス |
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| Research Abstract |
In this project, we investigated the regulatory mechanisms in gene expression mediated by cAMP signal transduction system under stress conditions such as desiccation, high salt concentration and nitrogen depletion in the cyanobacterium Anabaena sp. strain PCC 7120. A DNA microarray analysis showed that desiccation stress caused upregulation of genes for trehalose metabolism. Desiccation tolerance was connected with the ability to express many essential genes of cell metabolism when once dried cells were exposed to wet conditions. Among genes induced by the rehydration, we determined a gene for transcription factor, ancrpB, which is activated by cAMP. Disruption of ancrpB resulted in lowering photosynthetic activity.
When NaCl was added to the medium, cellular cAMP was increased transiently and the expression of lots of genes was enhanced remarkably. This increase of cAMP and upregulation of gene expression were not observed in the cyaC gene disruptant. It was also found that irradiation of far-red light caused an increase in cellular cAMP level. We constructed a gene disruptant insensitive for far-red light in terms of cellular cAMP change and searched far-red light receptor protein using this disruptant. As a result, a far-red light sensory protein was identified. This protein AphC is a histidine kinase probably transmits the light signal to cognate response regulator protein. As concerns as nitrogen depletion, we found a response regulator gene which regulates heterocyst differentiation.
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