title: Occupancy and function of the -150 sterol regulatory element and -65 E-box in nutritional regulation of the fatty acid synthase gene in living animals.
abstract: Upstream regulatory factor (USF) and sterol regulatory element binding protein (SREBP) play key roles in the transcriptional regulation of the fatty acid synthase (FAS) gene by feeding and insulin. Due to the dual binding specificity of SREBP, as well as the presence of multiple consensus sites for these transcription factors in the FAS promoter, their physiologically relevant functional binding sites have been controversial. Here, in order to determine the occupancy of the putative USF and SREBP binding sites, we examined their protein-DNA interactions in living animals by using formaldehyde cross-linking and immunoprecipitation of chromatin and tested the function of these elements by employing mice transgenic for a reporter gene driven by various 5' deletions as well as site-specific mutations of the FAS promoter. We show that the -332 and -65 E-boxes are bound by USF in both fasted and refed mice, while the -150 SRE is bound by SREBP-1 only in refed mice. We also found that mutation of either the -150 SRE or the -65 E-box abolishes the feeding-induced activation of the FAS promoter in transgenic mice. Furthermore, in vivo occupancy of the FAS promoter by SREBP in the fed state can be prevented by mutation not only of the -150 SRE but, unexpectedly, of the -65 E-box as well. We conclude that the FAS promoter is activated during refeeding via the induced binding of SREBP to the -150 SRE and that USF binding to the -65 E-box is also required for SREBP binding and activation of the FAS promoter.
authors.affiliation: Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA.
authors.forename: Maria-Jesus
authors.initials: MJ
authors.lastname: Latasa
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Griffin
authors.forename: Yang Soo
authors.initials: YS
authors.lastname: Moon
authors.forename: Chulho
authors.initials: C
authors.lastname: Kang
authors.forename: Hei Sook
authors.initials: HS
authors.lastname: Sul
mesh_terms: D000818:Animals; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D064429:Fatty Acid Synthases / Q000096:biosynthesis* / Q000235:genetics*; D005557:Formaldehyde / Q000494:pharmacology; D017353:Gene Deletion; D015971:Gene Expression Regulation, Enzymologic; D017930:Genes, Reporter; D051379:Mice; D008822:Mice, Transgenic; D008954:Models, Biological; D008957:Models, Genetic; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism; D051780:Sterol Regulatory Element Binding Protein 1; D013997:Time Factors; D014157:Transcription Factors; D014158:Transcription, Genetic
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D002843:Chromatin; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; C497388:Srebf1 protein, mouse; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors; D005557:Formaldehyde; D012313:RNA; D064429:Fatty Acid Synthases; D012260:Ribonucleases