| Project/Area Number |
09440267
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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 | Osaka University |
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Principal Investigator |
TATSUO Kakimoto Graduate School of Science Osaka University Research associate, 大学院・理学研究科, 助手 (70214260)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥10,900,000 (Direct Cost: ¥10,900,000)
Fiscal Year 1999: ¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1998: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 1997: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Keywords | cytokinin / Signal transduction / CKI1 / CKI2 / CKH1 / CKH2 / histidine kinase / 受容体 / シロイヌナズナ / MSH / シュート / カルス / アクティベーションタギング / 再生 |
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| Research Abstract |
This research was aimed at a better understanding of the cytokinin signaling pathway. For this purpose we have isolated Arabidopsis mutants that exhibit altered responses to cytokinins. We used either a strong transcriptional enhancer(4x35s enhancer) or a chemical as a mutagen. We previously isolated the cki1 and cki2 mutants, which exhibit constitutive cytokinin responses, among transformants with the strong transcriptional enhancer. In this study we have isolated the causal gene for cki2 mutant, and shown that the gene codes for a histidine kinase. The typical feature of the CK12 product is that it is predicted to reside at the cytoplasm, while all other histidine kinases in Arabidopsis are predicted to reside at the palsmamembrane. In the cki2 mutant, the 4x 35S enhancer was inserted in the coding region of the CK12 gene. Transcription of the CK12 gene initiated within the enhancer, probably resulting in the production of a product lacking part of its Nterminal region. We have also isolated the causal genes for cytokinin hyper and less-sensitive mutants, ckh1 and ckl1 respectively, which were isolated from an EMS mutagenized population. The CKH1 gene code for a product with similarity to TAFs, which are members of the transcriptional initiation complex. The CKL1 gene coded for a histidine kinase, emphasizing the importance of the two-component systems in cytokinin perception.
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