Orphan receptors chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) and retinoid X receptor (RXR) activate and bind the rat cholesterol 7 alpha-hydroxylase gene (CYP7A)

Title

Orphan receptors chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) and retinoid X receptor (RXR) activate and bind the rat cholesterol 7 alpha-hydroxylase gene (CYP7A)

Creator

Stroup D; Crestani M; Chiang J Y L

Publisher

Journal of Biological Chemistry

Date

1997
1997-04

Description

The cholesterol 7 alpha-hydroxylase gene (CYP7A) is transcriptionally regulated by a number of factors, including hormones, bile acids, and diurnal rhythm. Previous studies have identified a region from nucleotides (nt) -74 to -55 of the rat CYP7A promoter that enhanced bile acid repression of the SV40 early promoter, as assayed with a luciferase reporter gene in transiently transfected HepG2 cells. The rat CYP7A promoter/reporter activity was strongly stimulated by cotransfection with an expression plasmid encoding the nuclear hormone receptor chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) in a dose-dependent manner. Site-directed mutagenesis in the region of nt -74 to -55 altered this stimulation. Recombinant COUP-TFII expressed in HepG2 or COS-1 cells were found to bind to nt -74 -55 and nt -149 -128 probes by electrophoretic mobility shift assay (EMSA) and by supershifting the corresponding band with COUP-TFII-specific antibodies. The region of nt -176 -117 was previously mapped as a retinoic acid response region and was found to bind retinoid X receptor (RXR). EMSA supershift assays of wild-type and mutant oligomers using antibody against RXR revealed that the sequences between nt -145 and -134 were important for RXR binding. We conclude that COUP-TFII stimulates the transcriptional activity of the rat CYP7A promoter by binding to the sequences between nt -74 to -54 and nt -149 to -128. RXR may stimulate CYP7A gene transcription by binding to a direct repeat of the hormone response element separated by one nucleotide located at nt -146 -134.

Subject

arp-1; bile acids; Biochemistry & Molecular Biology; cloning; expression; liver; messenger-rna; regulatory protein-1; response elements; superfamily; thyroid-hormone

Identifier

n/a

Format

Journal Article

URL Address

n/a

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Rights

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Pages

9833-9839

Issue

15

Volume

272

Citation

Stroup D; Crestani M; Chiang J Y L, “Orphan receptors chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) and retinoid X receptor (RXR) activate and bind the rat cholesterol 7 alpha-hydroxylase gene (CYP7A),” NEOMED Bibliography Database, accessed May 13, 2021, https://neomed.omeka.net/items/show/8114.

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