1991 Fiscal Year Final Research Report Summary
Mechanisms of Radiation-Induced Apoptosis
| Project/Area Number |
02680176
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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 |
放射線5生物学
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| Research Institution | National Institute of Radiological Sciences (NIRS) |
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Principal Investigator |
OHYAMA Harumi NIRS, Division of Radiation Health, Sinior Research Official, 障害臨床研究部, 主任研究官 (70160645)
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| Co-Investigator(Kenkyū-buntansha) |
MITA Kazuei NIRS, Division of Biology. Senior Research Official, 生物研究部, 主任研究官 (30159165)
YAMADA Takeshi NIRS, Division of Biology, Division Head, 生物研究部, 室長 (30166714)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Apoptosis / Radiation-induced cell death / Thymocytes / Thymic lymphoma / Radiation sensitivity / Chromatin DNA fragmentation / Ubiquitin gene expression / apoptosis |
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| Research Abstract |
Thymocytes show typical apoptosis within a few hours following irradiation. Analysis of proteins with two deminsional gel electrophoresis revealed that a few proteins changed associated with the cell death. Inhibitors of protein synthesis and proteinase suppressed the cell death. Threfore, it is supposed that protein synthesis as well as protein degradation playsarole in the development of apoptosis. Ubiquitin gene expression increased slightly in the earlier phase and decreased thereafter in progression of the cell death. Chromatin DNA fragmentation into oligonucteosomal units represents the most characteristic biochemical event in apoptosis. We established microgel electrophoresis technique to detect the DNA cleavage. Results revealed that apoptotic cells showed similar migration pattern with a tear-drop shaped fragmented DNA tail and non-migrating DNA core particle, while viable cells exhibited no DNA migration. The findings indicate that apoptotic breakage of DNA in X-irradiated thymocytes is an "all or none" type event. In the present study, we found several extremely radiosensitive thymic lymphoma cell lines establised in our institute. These cells showed typical apoptosis within a few hours following low doses X-irradiation. Characteristic DNA fragmentation could be detected both by micro and macro get electrophoresis of DNA. Colony forming ability decreased with low doses X-irradiation. Further study on the mechanism of radiation induced apoptosis is now in progress.
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