| Project/Area Number |
11671834
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Morphological basic dentistry
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| Research Institution | Kyushu Dental College |
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Principal Investigator |
NISHIHARA Tatsuji Kyushu Dental College. Department of Oral Microbiology. Professor., 歯学部, 教授 (80192251)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2000: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | periodontopathic bacteria / protein toxin / apoptosis / cell cycle arrest / p21 / p53 / intracellular signal transduction / CDT / 毒素 / 細胞周期の停止 / G2 / M期 / 歯周炎 / Bcl-2 / 細胞膨化 |
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| Research Abstract |
The cytolethal distending toxin (CDT) from Actinobacillus actinomycetemcomitans was previously shown to induce cell cycle arrest in G2/M phase in Hela cells. In the present study, we demonstrated that the CDT from A.actinomycetemcomitans induced G2 cell cycle arrest in the B cell hybridoma cell line, HS-72 by flow cytometric analysis. The mechanism of CDT-induced cell cycle arrest was investigated using HS-72 cells. The CDT up-regulated the expression of cyclin-dependent kinase inhibitor p21CIP1/WAF1 and tumor-suppressor protein p53. The ectopic expression of human papilloma virus type-16 E6/E7 abolished the CDT-induced expression of p53. However, E6/E7 expression had no effect on the expression of p21CIP1/WAF1 and G2 cell cycle arrest in HS-72 cells cultured with the CDT.Furthermore, overexpression of adominant negative p53 mutant did not inhibit the CDT-mediated p21CIP1/WAF1 expression and G2 cell cycle arrest in HS-72 cells. These results indicate that the CDT from A.actinomycetemcomitans induce p21CIP1/WAF1 expression and G2 cell cycle arrest in B lineage cells by p53-independent pathways. Together with additional observations on Hela and COS-1 cells cultured with the CDT from A.actinomycetemcomitans, the results in the present study suggest the CDT-induced p21CIP1/WAF1 may promote G2 cell cycle arrest in mammmalian cells.
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