1997 Fiscal Year Final Research Report Summary
Analysis of the Mechanisms of Cell and Tissue Specific Expression of the Insulin Receptor Substrate, IRS-1 Gene.
| Project/Area Number |
08680747
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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 |
Molecular biology
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| Research Institution | KUMAMOTO UNIVERSITY |
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Principal Investigator |
ARAKI Eiichi KUMAMOTO UNIVERSITY,SCHOOL OF MEDICINE,LECTURER, 医学部・附属病院, 講師 (10253733)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAMURA Nobuhiro KUMAMOTO UNIVERSITY,SCHOOL OF MEDICINE,ASSISTANT PROFESSOR, 医学部・附属病院, 助手 (40274716)
SHIROTANI Tetsuya KUMAMOTO UNIVERSITY,SCHOOL OF MEDICINE,ASSISTANT PROFESSOR, 医学部・附属病院, 助手 (30274715)
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| Project Period (FY) |
1996 – 1997
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| Keywords | insulin / promoter / IRS-1 / gene / C / EBP / E box |
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| Research Abstract |
The results are summarized as follows.
IRS-1 is one of the major substrates of insulin receptor tyrosine kinase and mediates multiple insulin signals downstream.Tp elucidate the molecular mechanisms of the tissue specific regulation of IRS-1, we have studied the cis-acting elements and trans-acting factors in CHO and HepG2 cells.
Using the CAT (Chloramphenicol acetyltransferase) assay with the various deletion mutants of the IRS-1 promoter-CAT fusion plasmids, several regions responsible for positive or negative regulation in each cells were identified.A region from-1645 to-1585 bp which regulated expression negatively in CHO cells and positivity in HepG2 cells, was further analyzed.Within this region a fragment from-1645 to-1605bp up-regulated the IRS-1 promotor only in HepG2 cells, whereas a fragment from-1605 to-1585bp down-regulated only in CHO cells.
In the gel mobility shift assay, several nucler proteins which bind to these fragments were detected, and among them, two nuclear proteins which bind to a potential E box (nt-1635--1630) , and two nuclear proteins which bind to a potential C/EBP binding site (nt-1599--1591) were identified in HepG2 and CHO cells, respectively.
CAT assays using promoters mutated at the E box or at the C/EBP binding site revealed that these sequences were responsible for cell spcific regulation of the IRS-1 gene.
We therefore concluded that the two nulclear proteins which bind to the E box regulate IRS-1 gene expression positively in HepG2 cells, and the two nuclear proteins which bind to the C/EBP binding site regulate it negatively in CHO cells.
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[Publications] S.Ure, E.Araki, H.Kishikawa, T.Shirotani, M.Todaka, S.Isami, S.Shimada, R.Yoshimura, K.Matsuda, S.Motoyoshi, N.Miyamura, C.R.Kahn & M.Shichiri: "Molecular scanning of the IRS-1 gene in Japanese patients with non-insulin-dependent diabetes mellitus : identification of five novel polymorphisims in IRS-1 gene." Diabetologia. 39. 600-608 (1996)
Description
「研究成果報告書概要(欧文)」より
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[Publications] R.Yoshimura, E.Araki, S.Ura, T.Mikio, K.Tsuruzoe, N.Furukawa, H.Motoshima, K.Yoshizato, K.Kaneko, K.Matsuda, H.Kishikawa & M.Shichiri: "Impact of natural IRS-1 mutations on insulin signals ; mutations of IRS-1 in the PTB domain and near SH2 protein binding sites results in impaired function at different steps of IRS-1 signaling." Diabetes. 46. 929-936 (1997)
Description
「研究成果報告書概要(欧文)」より
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