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

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

Stroup D; Crestani M; Chiang J Y

The Journal of biological chemistry

1997

1997-04

The cholesterol 7alpha-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

Animals; Rats; *Gene Expression Regulation; Cholesterol 7-alpha-Hydroxylase/*genetics/metabolism; Nuclear Proteins/*metabolism; Chickens; Transcription Factors/*metabolism; DNA-Binding Proteins/*metabolism; Retinoid X Receptors; COUP Transcription Factor II; COUP Transcription Factors; Circadian Rhythm; COUP Transcription Factor I; Recombinant Proteins/genetics/metabolism; Receptors; Models; Genetic; Enzymologic; Molecular; Electrophoresis; Polyacrylamide Gel; Promoter Regions; *Receptors; Steroid; Glucocorticoid/*genetics; Retinoic Acid/*metabolism

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

9833–9839

15

272