Transcriptional activation of the stearoyl-CoA desaturase 2 gene by sterol regulatory element-binding protein/adipocyte determination and differentiation factor 1.
To identify genes that are transcriptionally activated by sterol regulatory element-binding proteins (SREBPs), we utilized mRNA differential display and mutant cells that express either high or low levels of transcriptionally active SREBP. This approach identified stearoyl-CoA desaturase 2 (SCD2) as a new SREBP-regulated gene. Cells were transiently transfected with reporter genes under the control of different fragments of the mouse SCD2 promoter. Constructs containing >199 base pairs of the SCD2 proximal promoter were activated following incubation of cells in sterol-depleted medium or as a result of co-expression of SREBP-1a, SREBP-2, or rat adipocyte determination and differentiation factor 1 (ADD1). Electromobility shift assays and DNase I footprint analysis demonstrated that recombinant SREBP-1a bound to a novel cis element (5'-AGCAGATTGTG-3') in the proximal promoter of the SCD2 gene. The finding that the endogenous SCD2 mRNA levels were induced when wild-type Chinese hamster ovary fibroblasts were incubated in sterol-deficient medium is consistent with a role for SREBP in regulating transcription of the gene. These studies identify SCD2 as a new member of the family of genes that are transcriptionally regulated in response to changing levels of nuclear SREBP/ADD1. In addition, the sterol regulatory element in the SCD2 promoter is distinct from all previously characterized motifs that confer SREBP- and ADD1-dependent transcriptional activation.
Tabor
D E
DE
Department of Biological Chemistry, University of California, Los Angeles, California 90095, USA.
Kim
J B
JB
Spiegelman
B M
BM
Edwards
P A
PA
D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins; D006224:Cricetinae; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D018257:Helix-Loop-Helix Motifs; D007527:Isoenzymes / Q000235:genetics*; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D013230:Stearoyl-CoA Desaturase / Q000235:genetics*; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D007527:Isoenzymes; D009687:Nuclear Proteins; D012333:RNA, Messenger; C497388:Srebf1 protein, mouse; C497389:Srebf1 protein, rat; C497391:Srebf2 protein, mouse; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D014157:Transcription Factors; D013230:Stearoyl-CoA Desaturase