2002 Fiscal Year Final Research Report Summary
Moleculer physiology of cAMP signal transduction in plant environmental response
| Project/Area Number |
12440223
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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
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| Research Institution | The University of Tokyo |
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Principal Investigator |
OHMORI Masayuki The University of Tokyo, Graduate School of Arts and Sciences, Professor, 大学院・総合文化研究科, 教授 (80013580)
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| Co-Investigator(Kenkyū-buntansha) |
SEKIMOTO Hiroyuki The University of Tokyo, Graduate School of Arts and Sciences, Research Assistant, 大学院・総合文化研究科, 助手 (20281652)
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| Project Period (FY) |
2000 – 2002
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| Keywords | cAMP / photoreceptor / cyanobacteria / signal transduction / adenylate cyclase / cell motility / microarray / desiccation stress |
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| Research Abstract |
Changes in cellular cAMP content induced by monochromatic light of various wavelengths were determined in the cyanobacterium Anabaena cylindrica. Irradiation with monochromatic red light caused a rapid decrease in cAMP content. In contrast, far-red light caused a rapid increase in its content. The effects of red and far-red light were reversible, suggesting involvement of a prototype phytochrome as the photoreceptor for cAMP-mediated light-responsive signal transduction.
A photoreceptor having phosphorylation capability and which might control the activity of CyaC via the phosphotransfer reaction has been predicted. For the mutant analysis, we first surveyed approximately 150 amino acid residues that are recognized as chromophore binding GAF domain in Anabaena genome, and determined the 23 chromophore binding GAF domains in the 15 ORFs. And then disrupted these ORFs by the insertion of antibiotic restriction cassettes. We found that the all2699 disruptant did not respond to far-red light. The ORF all2699 named aphC encodes a protein with 920 amino acids.
We have isolated twelve genes for Cya from various cyanobacteria. Those proteins, known as cAMP-forming enzymes, are classified into 6 groups by their deduced amino acid sequences. The Cya catalytic domains were C-terminal, whereas various putative input domains were N-terminal in all Cya proteins. Four Cya proteins had GAF domain(s) and the four GAF domains of CyaBl and CyaB2 were predicted to bind cGMP. Disruption of cyaC caused no response of cellular cAMP to red and far-red light irradiation.
The target genes for SYCRP1, a cyanobacterial cAMP receptor protein, were surveyed using a DNA microarray method. Total RNAs were extracted from a wild-type strain and a sycrpl disruptant of Synechocystis sp. PCC 6803, and the respective gene expression levels were compared The expression levels of six genes (slr1667, slr1668, slr2015, slr2016, slr2017, and slr2018) were clearly decreased by the disruption of the sycrpl gene.
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