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Titolo:
HNF4 and COUP-TFII interact to modulate transcription of the cholesterol 7alpha-hydroxylase gene (CYP7A1)
Autore:
Stroup, D; Chiang, JYL;
Indirizzi:
NE Ohio Univ, Coll Med, Dept Biochem & Mol Pathol, Rootstown, OH 44272 USANE Ohio Univ Rootstown OH USA 44272 & Mol Pathol, Rootstown, OH 44272 USA
Titolo Testata:
JOURNAL OF LIPID RESEARCH
fascicolo: 1, volume: 41, anno: 2000,
pagine: 1 - 11
SICI:
0022-2275(200001)41:1<1:HACITM>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
HEPATOCYTE NUCLEAR FACTOR-4; HORMONE-RECEPTOR SUPERFAMILY; RETINOIC ACID RECEPTORS; ORPHAN RECEPTORS; RESPONSE ELEMENTS; THYROID-HORMONE; MESSENGER-RNA; DNA-BINDING; BILE-ACIDS; PROMOTER;
Keywords:
bile acid synthesis; hepatocyte nuclear factor 4; chicken ovalbumin upstream promoter transcription factor II; orphan receptors; transcriptional regulation; cholesterol metabolism;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Chiang, JYL NE Ohio Univ, Coll Med, Dept Biochem & Mol Pathol, POB 95, Rootstown, OH 44272 USA NE Ohio Univ POB 95 Rootstown OH USA 44272 stown, OH 44272 USA
Citazione:
D. Stroup e J.Y.L. Chiang, "HNF4 and COUP-TFII interact to modulate transcription of the cholesterol 7alpha-hydroxylase gene (CYP7A1)", J LIPID RES, 41(1), 2000, pp. 1-11

Abstract

The gene for cholesterol 7 alpha-hydroxylase (CYP7A1) contains a sequence at nt -149 to -118 that was found to play a large role in determining the overall transcriptional activity and regulation of the promoter. Hepatocyte nuclear factor 4 (HNF4) and chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) synergistically activate transcription of the CYP7A1 promoter, Transactivation of CYP7A1 by HNF4 in the human hepatoma cell line, HepG2, was enhanced by cotransfection with COUP-TFII or the basal transcription element binding protein (BTEB), HNF4 prepared from rat liver nuclear extracts bound to oligomers homologous to the nt -146 to -134 sequencesin electrophoretic mobility shift assays (EMSA), which corresponded to a conserved region containing a direct repeat of hormone response elements spaced by one nucleotide (DR1), The sequences surrounding this DR1 were found to be essential for the HNF4 transactivation. In vitro-translated COUP-TFIIwas found to bind the adjacent sequences from nt -139 to -128 (DRO), but COUP-TFII interacted with this region at a much lower affinity than to the COUP-TFII-site at nt -72 to -57 (DR4), Mutations at nt -139 to -128 or nt -72 to -57 reduced the COUP-TFII and HNF4 synergy; however, these COUP-TFII-binding sequences were not absolutely required for the cooperative effect ofHNF4 and COUP-TFII on transactivation. These results indicated that the observed transactivation was the result of protein/protein interactions facilitated by the juxtaposition of the binding elements.

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Documento generato il 27/10/20 alle ore 04:17:31