Sterol regulatory element binding protein binds to a cis element in the promoter of the farnesyl diphosphate synthase gene.
Sterol-regulated transcription of the gene for rat farnesyl diphosphate (FPP) synthase (geranyl-diphosphate:isopentenyl-diphosphate geranyltranstransferase, EC 2.5.1.10) is dependent in part on the binding of the ubiquitous transcription factor NF-Y to a 6-bp element within the proximal promoter. Current studies identify a second element in this promoter that is also required for sterol-regulated transcription in vivo. Mutation of three nucleotides (CAC) within this element blocks the 8-fold induction of FPP synthase promoter-reporter genes that normally occurs when the transfected cells are incubated in medium deprived of sterols. Gel mobility-shift assays demonstrate that the transcriptionally active 68-kDa fragment of the sterol regulatory element (SRE-1)-binding protein assays (SREBP-1) binds to an oligonucleotide containing the wild-type sequence but not to an oligonucleotide in which the CAC has been mutated. DNase 1 protection pattern (footprint) analysis indicates that SREBP-1 binds to nucleotides that include the CAC. Both the in vivo and in vitro assays are affected by mutagenesis of nucleotides adjacent to the CAC. Coexpression of SREBP with a wild-type FPP synthase promoter-reporter gene in CV-1 cells results in very high levels of reporter activity that is sterol-independent. In contrast, the reporter activity remained low when the promoter contained a mutation in the CAC trinucleotide. We conclude that sterol-regulated transcription of FPP synthase is controlled in part by the interaction of SREBP with a binding site that we have termed SRE-3. Identification of this element may prove useful in the identification of other genes that are both regulated by SREBP and involved in lipid biosynthesis.
Ericsson
J
J
Department of Biological Chemistry, University of California, Los Angeles 90095, USA.
Jackson
S M
SM
Lee
B C
BC
Edwards
P A
PA
D019883:Alkyl and Aryl Transferases; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins; D002478:Cells, Cultured; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D017930:Genes, Reporter; D051228:Geranyltranstransferase; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D051381:Rats; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors; D014162:Transfection; D014166:Transferases / Q000235:genetics*
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C497389:Srebf1 protein, rat; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors; D014166:Transferases; D019883:Alkyl and Aryl Transferases; D051228:Geranyltranstransferase