| Project/Area Number |
03660083
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
応用生物化学・栄養化学
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| Research Institution | Kyoto Institute of Technology (1992)
Kyoto University (1991) |
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Principal Investigator |
IKURA Koji Kyoto Institute of Technology Faculty of Engineering and Design Department of Chemistry and Materials Technology Associate Professor, 工芸学部, 助教授 (00101246)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1992: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Transglutaminase / Interleukin-6 / Acute-phase response / Transglutaminase gene / Promoter region / トランスグルタミナ-ゼ / インタ-ロイキンー6 / 遺伝子発現 |
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| Research Abstract |
This research project aims to understand the physiological functions and regulatory mechanism of gene expression of the protein crosslinking enzyme transglutaminase on the molecular level. The following results were obtained.
1. Treatment of human hepato blastoma HepG2 cells with interleukin-6 (IL-6) increased their transglutaminase activity in a timeand dose-dependent way. Dexamethasone strengthened the stimulation by IL-6. Half-maximum stimulation of transglutaminase activity in the cells occurred at a dose of 40 pM IL-6 regardless of the presence of dexamethasone. Based on its immunoreactivity, the transglutaminase induced was identified as tissue-type transglutaminase. Immunoblot analysis showed that the increase in transglutaminase activity was related to an increase in the amount of transglutaminase protein. Nothern blot analysis showed that exposure of HepG2 cells to IL-6 increased the mRNA level of the enzyme, and the increase was detectable 3 h after IL-6 was added. Induction of the mRNA was maximum between 10 and 14 h. The increase in the mRNA was not blocked by the presence of cycloheximide, suggesting that the increase was independent of protein synthesis. Injections of substances that induces inflammation such as turpentine and lipopolysaccharides into mice increased the liver transglutaminase activity. These results indicated that transglutaminase may be involved in some biological processes in hepatocytes regulated by IL-6 signaling.
2. A 5' flanking region of the guinea pig liver transglutaminase gene was cloned and sequenced. The sequence for TATA box and potential binding sites of some regulatory factors were found in this region. The promoter activity of this region was shown by transfecting its fusion-construct with the chloramphenicol acetyltransferase gene into human hepatoblastoma HepG2 cells. The promoter activity was enhanced by interleukin-6.
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