Differential regulation of human and mouse orphan nuclear receptor small heterodimer partner promoter by sterol regulatory element binding protein-1.
Small heterodimer partner (SHP; NR0B2) is an unusual orphan nuclear receptor that lacks a conventional DNA-binding domain and acts as a modulator of transcriptional activities of a number of nuclear receptors. Herein, we report that the human SHP promoter (hSHP) is activated by sterol regulatory element-binding protein-1 (SREBP-1), which regulates the expression of various genes involved in cholesterol and fatty acid synthesis. Overexpression of SREBP-1 activated the human but not mouse SHP promoter, although SREBP-2 had little effect on the SHP promoter in CV-1 cells. Serial deletion reporter assays revealed that SREBP-1-responsive region is located within the sequences from -243 to -120 bp in the hSHP promoter. DNase I footprinting, gel shift assays, and chromatin immunoprecipitation assays demonstrated that SREBP-1 binds directly to the hSHP promoter. Site-directed mutagenesis made it clear that the hSHP promoter activation by SREBP-1 is mostly mediated by the SRE1 (-186 to -195 bp) in the hSHP promoter, which is not conserved in the mouse SHP promoter. Moreover, adenovirus-mediated overexpression of SREBP-1c/ADD-1 induced SHP mRNA expression and repressed CYP7A1 expression in HepG2 cells. Finally, we found that a four-nucleotide deletion (-195CT-GAdel) in the hSHP promoter, which is reported to be associated with altered body weight and insulin secretion in human, coincides with the SRE1. This mutation strongly decreased both basal and SREBP-1 dependent activities of the hSHP promoter, because of the reduced binding of SREBP-1 to the mutated SRE1. Overall, our results demonstrate a differential regulation of human and mouse SHP promoters by SREBP-1. We propose a possible role of SREBP-1 in the species differential regulation of cholesterol and bile acid homeostasis via a novel mechanism of up-regulation of the hSHP gene expression.
Kim
Han-Jong
HJ
Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Kwangju 500-757, Republic of Korea.
Kim
Joon-Young
JY
Kim
Ju-Youn
JY
Park
Sang-Kyu
SK
Seo
Ji-Ho
JH
Kim
Jae Bum
JB
Lee
In-Kyu
IK
Kim
Kyung-Sup
KS
Choi
Hueng-Sik
HS
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001835:Body Weight; D022762:CCAAT-Enhancer-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D003850:Deoxyribonuclease I / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D017353:Gene Deletion; D005786:Gene Expression Regulation; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D013997:Time Factors; D014157:Transcription Factors / Q000096:biosynthesis; D015533:Transcriptional Activation; D014162:Transfection; D015854:Up-Regulation
D022762:CCAAT-Enhancer-Binding Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D005227:Fatty Acids; D007328:Insulin; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; C497387:SREBF1 protein, human; C497390:SREBF2 protein, human; C497388:Srebf1 protein, mouse; C497391:Srebf2 protein, mouse; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D014157:Transcription Factors; C099713:nuclear receptor subfamily 0, group B, member 2; D004247:DNA; D002784:Cholesterol; D008156:Luciferases; D003850:Deoxyribonuclease I