出版社：American Society for Biochemistry and Molecular Biology
摘要：The cytosolic acyl-coenzyme A thioesterase I (Acot1) is an enzymethat hydrolyzes long-chain acyl-CoAs of C12-C20-CoA in chainlength to the free fatty acid and CoA. Acot1 was shown previouslyto be strongly upregulated at the mRNA and protein level inrodents by fibrates. In this study, we show that Acot1 mRNAlevels were increased by 90-fold in liver by treatment withWy-14,643 and that Acot1 mRNA was also increased by 15-foldin the liver of hepatocyte nuclear factor 4 (HNF4) knockoutanimals. Our study identified a direct repeat 1 (DR1) locatedin the Acot1 gene promoter in mouse, which binds the peroxisomeproliferator-activated receptor (PPAR) and HNF4. Chromatinimmunoprecipitation (ChIP) assay showed that the identifiedDR1 bound PPAR/retinoid X receptor (RXR) and HNF4, whereasthe binding in ChIP was abrogated in the PPAR and HNF4 knockoutmouse models. Reporter gene assays showed activation of theAcot1 promoter in cells by the PPAR agonist Wy-14,643 aftercotransfection with PPAR/RXR. However, transfection with a plasmidcontaining HNF4 also resulted in an increase in promoter activity.Together, these data show that Acot1 is under regulation byan interplay between HNF4 and PPAR.Supplementary key words peroxisome proliferator response element • peroxisome proliferator-activated receptor • direct repeat 1 • acyl-coenzyme A • lipid metabolism • hepatic nuclear factor 4Abbreviations: Acot1, acyl-coenzyme A thioesterase I; ChIP, chromatin immunoprecipitation; DR1, direct repeat 1; EMSA, electromobility shift assay; HNF4, hepatic nuclear factor 4; MCAD, medium-chain acyl-coenzyme A dehydrogenase; OTC, ornithine transcarbamylase; PPAR, peroxisome proliferator-activated receptor ; PPRE, peroxisome proliferator response element; RXR, retinoid X receptor
(HNF4
