Peroxisome proliferator-activated receptor mediates induction of the mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase gene by fatty acids

• Published in: The Journal of biological chemistry Vol. 269; no. 29; pp. 18767 - 18772
• Main Authors: J C Rodríguez, G Gil-Gómez, F G Hegardt, D Haro
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 22-07-1994
• Subjects: Animals; Base Sequence; Binding Sites; Biological and medical sciences; Clofibrate - pharmacology; Consensus Sequence; Enzyme Induction; Fatty acids; Fatty Acids - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic; HeLa Cells; Humans; Hydroxymethylglutaryl-CoA Synthase - genetics; Macromolecular Substances; Metabolic regulation; Mitochondria; Mitochondria - enzymology; Mitocondris; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Oligonucleotide Probes - chemistry; Promoter Regions, Genetic; Rats; Receptors, Cytoplasmic and Nuclear - metabolism; Receptors, Retinoic Acid; Regulació del metabolisme; Retinoid X Receptors; RNA, Messenger - genetics; Transcription Factors - metabolism; Transcription. Transcription factor. Splicing. Rna processing; Tumor Cells, Cultured; Àcids grassos; Transcription; Rat; Enzyme; Transcription promoter; Hydroxymethylglutaryl-CoA synthase; Rodentia; Lipids; Lyases; Gel retardation technique; Fatty acids; Peroxisome proliferator; Oxo-acid-lyases; Carbon-carbon lyases; Vertebrata; Mammalia; Regulatory sequence; Biological receptor
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(17)32234-2

Fatty acids induce an increase in the transcription of the mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase
gene, which encodes an enzyme that has been proposed as a control site of ketogenesis. We studied whether the peroxisome proliferator-activated
receptor (PPAR) is involved in the mechanism of this transcriptional induction. We found that cotransfection of a rat mitochondrial
HMG-CoA synthase promoter-chloramphenicol acetyltransferase reporter plasmid and a PPAR expression plasmid in the presence
of the peroxisome proliferator clofibrate led to a more than 30-fold increase in chloramphenicol acetyltransferase activity,
relative to the activity in the absence of both PPAR and inducer. Linoleic acid, a polyunsaturated fatty acid, increased this
activity as potently as does clofibrate and more effectively than does monounsaturated oleic acid. We have identified, by
deletional analysis, an element located 104 base pairs upstream of the mitochondrial HMG-CoA synthase gene, which confers
PPAR responsiveness to homologous and heterologous promoters. This is the first example of a peroxisome proliferator-responsive
element (PPRE) in a gene encoding a mitochondrial protein. This element contains an imperfect direct repeat that is similar
to those described in the PPREs of other genes. Furthermore, gel retardation and cotransfection assays revealed that, as for
other genes, PPAR heterodimerizes with retinoid X receptor and that both receptors cooperate for binding to the mitochondrial
HMG-CoA synthase PPRE and subsequent activation of the gene. In conclusion, our data demonstrate that regulation of mitochondrial
HMG-CoA synthase gene expression by fatty acids is mediated by PPAR, supporting the hypothesis that PPAR has an important
role at the transcriptional level in the regulation of lipid metabolism.