1998 Fiscal Year Final Research Report Summary
Analysis of the protein carboxyl methyltransferase gene as a brain specific repair enzyme
| Project/Area Number |
09670992
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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 |
Psychiatric science
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| Research Institution | Ehime University |
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Principal Investigator |
MIZOBUCHI Mutsuhiko Ehime University, assistant professor, 医学部 附属病院, 講師 (00166042)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEDA Ryohei Ehime University, lecturer, 医学部, 助手 (60271087)
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| Project Period (FY) |
1997 – 1998
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| Keywords | methyltransferase / repair enzyme / PCR / cDNA / X-irradiation |
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| Research Abstract |
An isoaspartyl protein carboxyl methyltransferase (PIMT) catalyzes the methyl esterification of D-aspartyl and L-isoaspartyl residues in proteins and peptides, converts the altered residues to normal L-aspartic acid residues, and is presumed to function in the repair of damaged proteins by racemization and deamidation. We have reported that the PIMT gene is expressed mainly in the brain and testis and have determined these cDNA sequences. We have also proved that the mRNA levels in cataractous lens epithelia are significantly lower than those in normal age-matched lens tissue. It is postulated that low dose X-irradiation facilitates the proliferation and prolongs the survival rate of the cells in vivo and in vitro. The physiological benefit from low level ionizing radiation is called as radiation hormesis. In this study, we examined the change of the PIMT mRNA levels in rat cultured fibroblast cells stimulated by irradiation to clarify the mechanism of the hormesis effect. We compared the PIMT gene expression in the cultured cells after 0, 25, 50 and 75 cGy irradiation. Three days after 50 and 75 cGy irradiation, PIMT mRNA levels increased about 1.5 and 2 times, respectively. These results suggest that the PIMT might play an important role in the hormesis mechanism.
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