Basic Transcription Element Binding Protein (BTEB) Transactivates the Cholesterol 7α-Hydroxylase Gene (CYP7A)

Foti, Dolly; Stroup, Diane; Chiang, John Y.L.

doi:10.1006/bbrc.1998.9759

Cited by 22 publications

(17 citation statements)

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“…As has been shown recently the promoter of the ratelimiting enzyme in bile acid synthesis, cholesterol 7␣-hydroxylase (CYP7A), contains basic transcription element (BTE) and a Sp1 binding site in the Ϫ100/Ϫ82 region (21). Transient transfection assay have confirmed that BTEB1 was able to transactivate the CYP7A promoter/luciferase chimeric gene (21). Subsequently we may suggest that expression of another bile acid producing enzymes can be modulated by BTEB1 also.…”

Section: Figmentioning

confidence: 58%

“…On the other side we can not exclude the possibility that the same Sp1/AP2 binding sites in promoter of perMFE-2 are recognized by another nuclear receptors. As has been shown recently the promoter of the ratelimiting enzyme in bile acid synthesis, cholesterol 7␣-hydroxylase (CYP7A), contains basic transcription element (BTE) and a Sp1 binding site in the Ϫ100/Ϫ82 region (21). Transient transfection assay have confirmed that BTEB1 was able to transactivate the CYP7A promoter/luciferase chimeric gene (21).…”

Section: Figmentioning

confidence: 78%

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Characterization of the Promoter Region of the Human Peroxisomal Multifunctional Enzyme Type 2 Gene

Novikov

Kamps

2001

Biochemical and Biophysical Research Communications

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Section: Figmentioning

confidence: 58%

Section: Figmentioning

confidence: 78%

Characterization of the Promoter Region of the Human Peroxisomal Multifunctional Enzyme Type 2 Gene

Novikov

Kamps

2001

Biochemical and Biophysical Research Communications

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“…In contrast, human and hamster CYP7A1 are not stimulated by retinoic acid because they lack a DR5 motif (18). The corresponding sequence in the human gene instead binds CPF (26) and BTEB, a member of Sp1 family of transcription factors (27). Therefore, FXR may interact with CPF or BTEB and prevent them from activating human CYP7A1 transcription.…”

Section: Identification Of An Fxr Response Element In Cyp7a1mentioning

confidence: 99%

Farnesoid X Receptor Responds to Bile Acids and Represses Cholesterol 7α-Hydroxylase Gene (CYP7A1) Transcription

Chiang

Kimmel

Weinberger

et al. 2000

Journal of Biological Chemistry

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293

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Cholesterol 7␣-hydroxylase gene (CYP7A1) transcription is repressed by bile acids. The goal of this study is to elucidate the mechanism of CYP7A1 transcription by bile acid-activated farnesoid X receptor (FXR) in its native promoter and cellular context and to identify FXR response elements in the gene. In Chinese hamster ovary cells transfected with retinoid X receptor ␣ (RXR␣)/FXR, only chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA) were able to stimulate a heterologous promoter/reporter containing an ecdysone response element. In HepG2 cells, all bile acids (25 M) were able to repress CYP7A1/luciferase reporter activity, and only CDCA and DCA further repressed reporter activity when cotransfected with RXR␣/FXR. The concentration of CDCA required to inhibit 50% of reporter activity (IC 50 ) was determined to be approximately 25 M without FXR and 10 M with FXR. Deletion analysis revealed that the bile acid response element located between nucleotides ؊148 and ؊128 was the FXR response element, but RXR␣/FXR did not bind to this sequence. These results suggest that bile acid-activated FXR exerts its inhibitory effect on CYP7A1 transcription by an indirect mechanism, in contrast to the stimulation and binding of FXR to intestinal bile acid-binding protein gene promoter. Results also reveal that bile acid receptors other than FXR are present in HepG2 cells.

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“…[3][4][5]. In cultured cells and rodents, several different DNA-binding proteins have been shown to regulate the transcription of the endogenous CYP7A1 gene in regard to diurnal variation (albumin D site-binding protein) (7,8), liver specificity (CYP7A1 promoter binding factor) (16), oxysterols (liver X receptor␣) (11,17), and bile acids (basic transcription element-binding protein) (18) and (farnesoid X receptor) (19). Transcriptional variation results in an almost concomitant change in CYP7A1 mRNA levels, suggesting that CYP7A1 mRNA displays rapid turnover (6 -8).…”

mentioning

confidence: 99%

One or More Labile Proteins Regulate the Stability of Chimeric mRNAs Containing the 3′-Untranslated Region of Cholesterol-7α-hydroxylase mRNA

Baker

Wang

Bell

et al. 2000

Journal of Biological Chemistry

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Multiple AUUUA elements similar to those that regulate the degradation of several different mRNAs are conserved in the 3-untranslated region (3-UTR) of cholesterol-7␣-hydroxylase (CYP7A1) mRNAs from several species. We examined if stabilization of mRNA decay could account for the >20-fold increase in the expression of CYP7A1 mRNA without a detectable change in transcription following dexamethasone treatment of rat hepatoma cells (L35 cells). Following RNA polymerase II-dependent transcription block or protein synthesis block, the decay of CYP7A1 mRNA displayed a short half-life (ϳ30 min). Control experiments showed that in cells pre-treated with a RNA polymerase II inhibitor, dexamethasone had no detectable effect on CYP7A1 mRNA decay. Stable expression of luciferase reporter mRNAs in L35 cells showed that the CYP7A1 3-UTR was required to observe a dexamethasone induction. To examine the hypothesis that a labile protein is required for dexamethasone-induced mRNA stabilization, cells were stably transfected with a tetracycline-repressible promoter that drives the expression of a green fluorescent protein analogue (ECFP) with or without the 3-UTR of CYP7A1. Cells expressing ECFP with the 3-UTR of CYP7A1 displayed a 3-fold dexamethasone induction of ECFP mRNA, whereas cells expressing ECFP without the 3-UTR did not. Moreover, specific block of the transcription of ECFP containing the 3-UTR by adding the tetracycline analogue doxycycline clearly displayed dexamethasone-induced stabilization of mRNA decay. These data provide compelling evidence that a putative labile protein and the 3-UTR of CYP7A1 act together to decrease the rate of CYP7A1 mRNA degradation.

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Basic Transcription Element Binding Protein (BTEB) Transactivates the Cholesterol 7α-Hydroxylase Gene (CYP7A)

Cited by 22 publications

References 0 publications

Characterization of the Promoter Region of the Human Peroxisomal Multifunctional Enzyme Type 2 Gene

Characterization of the Promoter Region of the Human Peroxisomal Multifunctional Enzyme Type 2 Gene

Farnesoid X Receptor Responds to Bile Acids and Represses Cholesterol 7α-Hydroxylase Gene (CYP7A1) Transcription

One or More Labile Proteins Regulate the Stability of Chimeric mRNAs Containing the 3′-Untranslated Region of Cholesterol-7α-hydroxylase mRNA

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