Characterization of a cholesterol response element (CRE) in the promoter of the cholesteryl ester transfer protein gene: functional role of the transcription factors SREBP-1a, -2, and YY1.
Cholesteryl ester transfer protein (CETP) is expressed in human adipocytes, where it acts to promote selective uptake of HDL-CE (Benoist, F., M. McDonnell, P. Lau, R. Milne, and R. McPherson. 1997. J. Biol. Chem. 272: 23572;-23577). In contrast to other major sterol-responsive genes such as 3-hydroxy-3-methylglutaryl coenzyme A reductase CETP expression is up-regulated rather than down-regulated in response to cholesterol. To define elements involved in cholesterol-mediated up-regulation of CETP gene expression, deletion derivatives of the CETP promoter were cloned into a luciferase reporter construct and transfected into the human liposarcoma cell line SW872, cultured in the presence or absence of lipoproteins. A fragment associated with a positive cholesterol response was identified between nucleotides -361 and -138 (relative to the initiation site of transcription) of the promoter. This region contains a tandem repeat of a sequence known to mediate sterol dependent regulation of the hamster HMG-CoA reductase gene. We have putatively denoted this region, the cholesterol response element (CRE). Using gel mobility shift assays we demonstrate that both YY1 and SREBP-1 interact with the CRE of CETP. Furthermore, in transient co-transfection experiments, both YY1 and SREBP-1a were found to trans-activate, in a dose-dependent manner, the luciferase activity of constructs harboring the CRE. We also demonstrate that SREBP-2, is able to trans-activate a luciferase construct harboring the CRE although much less effectively as compared to SREBP-1. Finally, functional analysis of the CRE confirms its regulatory role in modulating CETP gene expression through its interaction with YY1 and SREBP-1a.
Gauthier
B
B
Lipoprotein and Atherosclerosis Group, University of Ottawa Heart Institute, Ottawa, Canada K1Y 4E9.
Robb
M
M
Gaudet
F
F
Ginsburg
G S
GS
McPherson
R
R
D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins / Q000235:genetics*; D002784:Cholesterol / Q000378:metabolism*; D053480:Cholesterol Ester Transfer Proteins; D006224:Cricetinae; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D050981:Erythroid-Specific DNA-Binding Factors; D006023:Glycoproteins; D006801:Humans; D006888:Hydroxycholesterols / Q000097:blood; D008055:Lipids / Q000097:blood; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D017422:Sequence Analysis, DNA; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured; D050986:YY1 Transcription Factor; D016335:Zinc Fingers
D022762:CCAAT-Enhancer-Binding Proteins; C506642:CETP protein, human; D002352:Carrier Proteins; D053480:Cholesterol Ester Transfer Proteins; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D006023:Glycoproteins; D006888:Hydroxycholesterols; D008055:Lipids; D009687:Nuclear Proteins; D012333:RNA, Messenger; C497387:SREBF1 protein, human; C497390:SREBF2 protein, human; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D014157:Transcription Factors; D050986:YY1 Transcription Factor; C494698:YY1 protein, human; C007997:25-hydroxycholesterol; D004247:DNA; D002784:Cholesterol