2004 Fiscal Year Final Research Report Summary
Regulation of gene expression and functional analysis of an insulin-inducible transcription factor
| Project/Area Number |
15590933
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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 |
Metabolomics
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| Research Institution | University of Fukui (2004)
福井医科大学 (2003) |
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Principal Investigator |
YAMADA Kazuya University of Fukui, Faculty of Medical Sciences, Department of Biochemistry, Associate Professor, 医学部, 助教授 (20263238)
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| Project Period (FY) |
2003 – 2004
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| Keywords | insulin / transcription factor / SHARP-2 / diabetes mellitus / phosphoenolpyruvate carboxykinase |
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| Research Abstract |
Transcription of the rat fatty acid synthase (FAS) gene in the rat liver can be regulated by feeding a high-carbohydrate diet. A carbohydrate response element (ChoRE) located on the rat FAS gene promoter has been identified. We cloned a basic helix-loop-helix protein, enhancer of split-and hairy-related protein-2 (SHARP-2), as the cDNA of ChoRE-binding proteins. Northern blot analysis revealed that the levels of SHARP-2 mRNA increase, when a high-carbohydrate diet is fed to normal rats or when insulin is administered to diabetic rats. In primary cultured rat hepatocytes, insulin rapidly induced an accumulation of SHARP-2 mRNA and the increase was blocked by wortmannin and LY294002. In addition, nuclear run-on assay revealed that transcription of the rat SHARP-2 gene was induced by insulin. Thus, we conclude that insulin induces the transcription of the rat SHARP-2 gene via a phosphoinositide 3-kinase pathway. Next, we examined the issue of whether the expression of SHARP-2 mRNA is regu
… More
lated by insulin in other insulin-responsive cells, such as 3T3-L1 adipocytes and L6 myotubes. We found that SHARP-2 is also an insulin-inducible transcription factor in these cells and cyclic AMP also increased the level of SHARP-2 mRNA in both cells in an additive manner.
Then, the influence of the SHARP-2 transcriptional repressor on the expression of rat phosphoenolpyruvate carboxykinase (PEPCK) gene was examined. The adenovirus-mediated overexpression of SHARP-2 in H4IIE cells and primary cultured rat hepatocytes led to a decrease in the levels of PEPCK mRNA. Finally, when a SHARP-2 expression plasmid was transiently transfected with various reporter plasmids into MH1C1 cells, the promoter activity of a PEPCK reporter plasmid was specifically decreased. Based on these findings, we concluded that SHARP-2 is a potential repressor of PEPCK gene expression.
We also reported regulation of expression of the rat SHARP-2 gene by gonadotropins and molecular cloning and characterization of transcriptional regulatory mechanism of the gene. Less
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Research Products
(10 results)
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[Journal Article] Gene expression of basic helix-loop-helix transcription factor, SHARP-2, is regulated by gonadotropins in the rat ovary and MA-10 cells.2004
Author(s)
Yamada, K., Kawata, H., Mizutani, T., Arima, T., Yazawa, T., Matsuura, K., Show, Z., Sekiguchi, T., Yoshino, M., Kajitani, T., Miyamoto, K.
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Journal Title
Biol.Reprod. 70
Pages: 76-82
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] The rat enhancer of split-and hairy-related protein-2 gene : hepatic expression, genomic structure, and promoter analysis.2004
Author(s)
Hirano, S., Yamada, K., Kawata, H., Shou, Z., Mizutani, T., Shigematsu, Y., Mayumi, M., Miyamoto, K.
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Journal Title
Arch.Biochem.Biophys. 422
Pages: 81-90
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Insulin induces the expression of the SHARP-2/Stra13/DEC1 gene via a phosphoinositide 3-kinase pathway.2003
Author(s)
Yamada K., Kawata, H., Show, Z., Mizutani, T., Noguchi, T., Miyamoto, K.
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Journal Title
J.Biol.Chem. 278
Pages: 30719-30724
Description
「研究成果報告書概要(欧文)」より
