| Project/Area Number |
09671043
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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 |
内分泌・代謝学
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| Research Institution | Nagaoya University |
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Principal Investigator |
KAMBE Fukushi Nagoya Univ., Res.Inst.Environ.Med., Associate Professor, 環境医学研究所, 助教授 (00211871)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAYA Takashi Nagoya Univ., Res.Inst.Environ.Med., Professor Associate, 環境医学研究所, 助手 (80262913)
MURATA Yoshiharu Nagoya Univ., Res.Inst.Environ.Med., Professor, 環境医学研究所, 教授 (80174308)
SEO Hisao Nagoya Univ., Res.Inst.Environ.Med., Professor, 環境医学研究所, 教授 (40135380)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | Pax-8 / thyroperoxidase / redox / PDTC / TTF-1 / サイログロブリン / 転写調節因子 / システイン |
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| Research Abstract |
Thyroid-transcription factor Pax-8 is involved in thyroid-specific expression of thyroglobulin (TG) and thyroperoxidase (TPO) genes. Our previous study demonstrated that DNA-binding activity of Pax-8 is regulated by redox control mechanism. In the present study, we identified redox-sensitive cysteine in Pax-8 molecule. Several mutant Pax-8 cDNAs were constructed by 'enzymatic inverse PCR' to substitute cysteine codon with that of serine. These cDNAs were subjected to in vitro translation, and the binding activities of their products were examined by gel shift assay. Single substitution of Cys45 or Cys57 with serine did not affect the binding of Pax-8. However, when both cysteines were substituted with serines, redox regulation of the DNA binding was abolished, indicating that two cysteine residues, Cys-45 and Cys-57, in the paired domain are responsible for the redox regulation of Pax-8. We next examined redox regulation of thyroid cell functions using antioxidant pyrrolidine dithiocarbamate (PDTC). Rat thyroid FRTL-5 cells were treated with 40 muM PDTC.Northern analysis showed that PDTC induced a marked decrease in TPO and Pax-8 mRNA levels. However, it had no effect on TG and TTF-1 mRNA levels, indicating that PDTC effect is specific to the former two mRNAs. Consistent with the mRNA level, a decrease in DNA-binding activity of Pax-8 was observed. TTF-1 and TTF-2 binding was not altered by PDTC, suggesting that TPO expression is mainly regulated by Pax-8. Treatment of FRTL-5 cells with PDTC also induced a remarkable increase in thymidine incorporation, indicating increased cell growth. These results suggest that redox regulation is involved in the expression of differentiation markers and proliferation of thyroid cells.
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