| Autor: |
D E, Jensen, C B, Rich, A J, Terpstra, S R, Farmer, J A, Foster |
| Rok vydání: |
1995 |
| Předmět: |
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| Zdroj: |
The Journal of biological chemistry. 270(12) |
| ISSN: |
0021-9258 |
| Popis: |
We have recently identified a novel element (EFE 5/6) in the human elastin gene promoter that modulates the ability of insulin-like growth factor I (IGF-I) to up-regulate elastin gene transcription in aortic smooth muscle cells. In the present study, we have pursued the identification of those nuclear proteins binding to the EFE 5/6 element and affected by IGF-I treatment. Chelation inactivation and metal reactivation experiments together with supershift gel analyses demonstrated that Sp1 was one of the proteins affected by IGF-I. Southwestern and Western analyses showed that Sp1 was present in IGF-I nuclear extracts and capable of binding DNA after fractionation. Addition of retinoblastoma gene product (Rb) antibody mimicked the effect of IGF-I in gel shift analysis, suggesting that Sp1 binding may be regulated by an inhibitor normally associated with Rb. The fact that the phosphorylation state of Rb was affected by IGF-I was shown by Western blot analysis. The control smooth muscle cells transcribed the elastin gene at a high level without addition of IGF-I, so it is likely that disruption of Sp1 binding is the first step in allowing the binding of a more potent activating factor. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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