| Autor: |
Fuernkranz HA; Department of Cardiovascular Molecular Biology, Lederle Laboratories, American Cyanamid Co., Pearl River, NY 10965., Wang Y, Karathanasis SK, Mak P |
| Jazyk: |
angličtina |
| Zdroj: |
Nucleic acids research [Nucleic Acids Res] 1994 Dec 25; Vol. 22 (25), pp. 5665-71. |
| DOI: |
10.1093/nar/22.25.5665 |
| Abstrakt: |
Hepatocyte Nuclear Factor 4 (HNF-4), a liver-enriched orphan receptor of the nuclear receptor superfamily, is required for the expression of a wide variety of liver-specific genes including apoAI. To explore the possibility that site A of the apoAI gene enhancer might also be the target for HNF-4 without the interference of endogenous mammalian cell proteins that also bind to site A, we tested the ability of HNF-4 to activate transcription from site A in yeast cells. Electrophoretic mobility shift assays (EMSA) and Scatchard plot analysis demonstrated that yeast produced HNF-4 binds to site A with an affinity two times higher than that of yeast produced RXR alpha. Mapping analysis indicated that the 5' portion of site A containing two imperfect direct repeats (TGAACCCTTGACC) and the sequence of the trinucleotide spacer (CCT) between these imperfect repeats are critical determinants for selective binding and transactivation by HNF-4. Similar observations were obtained when these mutated versions of site A were evaluated by transient cotransfection assays in CV1 cells. We conclude that the unique structural determinants of site A in conjunction with the differential binding affinity of HNF-4 for site A may play a fundamental role in apoAI gene regulation. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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