1990 Fiscal Year Final Research Report Summary
Analysis of Function and Purification of Factors Defective in Cockayne Syndrome Cells
| Project/Area Number |
01480499
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Human genetics
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| Research Institution | Kumamoto University |
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Principal Investigator |
YAMAIZUMI Masaru Inst. for Medical Genetics, Professor, 医学部, 教授 (70107093)
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| Co-Investigator(Kenkyū-buntansha) |
HOTTA Nobuyuki Inst. for Medical Genetics, Instructor, 医学部, 助手 (50040572)
SUGANO Tatsuo Inst. for Medical Genetics, Instructor, 医学部, 助手 (00211300)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Cockayne syndrome / defective factors in Cockayne syndrome / DNA repair / Somatic cell genetics |
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| Research Abstract |
We obtained the following findings through the present study.
1) Microinjection of T4 endonuclease V into UV-irradiated group A and group B CS cells partially restored both RNA synthesis and protein synthesis, suggesting that CS cells have defects in the excision repair of pyrimidine dimers at least in some DNA regions. 2. Actually we could elucidate that there almost no removal of pyrimidine dimers from the ribosomal RNA fragment by using alkali-denaturing gel electrophoresis. 3. Cell fusion experiments between group A and group B CS cells and between CS cells ad XP-A cells revealed that the recovery of RNA synthesis was detected after 16 hours in the former experiment and 8 hours in the latter. This result suggests that the defecting factors in CS cells may be instable when exist by itself but stabilized when both factors are present together. 4. Microinjection with ATP or NAD into the nuclei did not restore RNA synthesis. 5. Injection with poly-ADP ribose synthetase or DNA kinase into the nuclei showed no effects as well. 6. Injection with normal cell extracts, however, partially restored the RNA synthesis in both group A and group B CS cells. 7. These defecting factors in CS cells were nuclear proteins, exist in a cell at a minimal essential amount and the activities were not induced by UV. The defecting factor in the group B (CS) cells was unstable compared to that of group A. 8. As for the case of CS accompanied with group B, the defecting factor (s) for group B XP was detected in the fraction which corresponded to the molecular mass of 600 kDa in the gelfiltration experiments and only this fraction stimulated the restoration of both UDS and RNA synthesis. This result suggested the involvement of a single gene in this complex disorder.
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