1999 Fiscal Year Final Research Report Summary
Gene regulation of prosteins related to renal function
| Project/Area Number |
09470236
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Kidney internal medicine
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| Research Institution | Tohoku University |
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Principal Investigator |
TAKEUCHI Kazuhisa Tohoku University, Graduate School of Med., Research Associa, 大学院・医学系研究科, 助手 (40260426)
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| Co-Investigator(Kenkyū-buntansha) |
SUGAWARA Akira Tohoku University, Graduate School of Med., Research Associa, 大学院・医学系研究科, 助手 (90270834)
ITOH Sadayoshi Tohoku University, Graduate School of Med., Professor, 大学院・医学系研究科, 教授 (40271613)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Thromboxane / Na-Cl transporter / NRF2 / PPAR / HFH-3 / transgenic rat / renal function / gen regulation |
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| Research Abstract |
1) We have studied the transcription regulation of rat thromboxane synthase (TXS) gene by peroxisome proliferator-activated receptor γ (PPARγ) in Mφ. The transcription activity of cloned 5'-flanking region (1.6 kb) of rat TXS gene (5'FL-TXS) was examined by luciferase reporter gene assay. TXS mRNA levels and transcription activity of 5'FL-TXS were inhibited by PPARγ. Deletion analysis showed that the element responsible for the PPARγ effect was located in a region containing the NF-E2/AP-1 site (-98/-88), which was indicated to be bound by NF-E2 related factor 2 (Nrf2). Finally, a direct interaction between PPARγ and Nrf2 was confirmed by GST pull-down assay. In conclusion, the Nrf2-binding site (-98/-88) is the major promoter of 5'FL-TXS in Mφ, which can be suppressed by activated PPARγ via a protein-protein interaction with Nrf2.
2)Thiazide-sensitive Na-Cl cotransporter (TSC) is localized exclusively to the renal distal convoluted tubule (DCT) in kidney. We examined the molecular mechanism of this renal TSC expression localization. We generated transgenic rats harboring the transcription regulatory region of TSC fused upstream of the LacZ gene. Immunohistochemical analysis clearly showed that LacZ gene expression was co-localized to cortical distal tubules with TSC, indicating that the 5'FL/rTSC regulates the renal tubule-specific expression of TSC. Transcriptional activity of the rTSC gene was stimulated by overexpression of HFH-3, and electrophoretic mobility-shift assay showed a direct binding of in vitro synthesized HFH-3 to the HFH-3/rTSC. In conclusion, the transcription regulatory region of TSC gene confers the DCT-specific gene expression in the kidney. The DCT-specific transcription factor HFH-3 may be involved in the renal tubule-specific transcription of TSC gene.
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