| Project/Area Number |
10450306
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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 |
生物・生体工学
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| Research Institution | Tokyo University of agriculture and Technology |
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Principal Investigator |
MATSUNAGA Tadashi Tokyo University of agriculture and Technology, Department of Biotechnology, Professor, 工学部, 教授 (10134834)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEYAMA Haruko Tokyo University of agriculture and Technology, Department of Biotechnology, Associate Professor, 工学部, 助教授 (60262234)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥12,200,000 (Direct Cost: ¥12,200,000)
Fiscal Year 2000: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1999: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1998: ¥7,600,000 (Direct Cost: ¥7,600,000)
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| Keywords | marine cyanobacteria / UV absorbing compounds / UV-A resistant growth / biopterin-glycoside / GroEL / myxoxanthophyll / CIRCE / SOS box / CIRCE因子 / シャペロニン / トランスポゾン / mRNA |
|---|
| Research Abstract |
A filamentous cyanobacterium Oscillatoria NKBG091600 can grow under UV-A irradiation with white light. The cyanobacterium produces biopterin-glycoside, UV-A absorbing compound, in the cell depending on the UV-A irradiation. In this report, molecular mechanisms of the UV-A tolerant growth of the cyanobacterium were studied. Under the growth of UV-A radiation, a protein of 60 kDa was highly expressed at 8 hours after irradiation. The expression of this protein was accompanied by an increase of biopterin-glucoside amount. N-terminal amino acid sequence of the 60 kDa protein was homologous to cyanobacterial GroEL which was known well as a heat shock protein in various organisms. Northern hybridization analysis showed that the level of groEL mRNA increased depending on the UV-A irradiation, showing that the induction of GroEL was due to the activation of transcription level. A genomic DNA fragment containing the GroESL operon (GroES+GroEL) in the cyanobacterium was cloned by using PCR with
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primers designed from those reported from cyanobacteria. By a detailed analysis of the gene structure, CIRCE (Controlled Inverted Repeat of Chaperone Expression) region was found at upper stream of GroES, while the distance between the CIRCE and GroES were two-fold longer than those in Synechococcus PCC 7942 and Synechocystis PCC 6803. A SOS box-like region was also found between the CIRCE and GroES.It was not found in Synechococcus PCC 7942 and Synechocystis PCC 6803. The SOS box-like region functioned as SOS regulator in E.coli cells. These differences in genome structure indicated that expression of GroESL iut the UV-A tolerant cyanobacterium was regulated by complex way comparing from those in other cyanobacteria. In addition to the increase of biopterin-glycosides and GroEL, myxoxanthophyll was also found to increase in the UV-A tolerant cyanobacterium. UV-A tolerance of the cyanobacterium resulted on complex mechanism containing at least three factors, (1) induction of biopterin-glycoside production, (2) induction of GroESL transcription, and (3) accumulation of carotenids and xanthophylls. Future studies will be required for developing the techniques for creation of UV-A tolerant organisms. Less
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