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Cloning and functional characterization of the 5′ regulatory region of the human mitochondrial glycerol‐3‐phosphate dehydrogenase gene: Lack of 3,5,3′‐triiodothyronine responsiveness in adipose tissue

Urcelay, Elena, Jareño, María A., Menaya, Juan, Parrilla, Roberto, Ayuso, Matilde S., Martín‐Requero, Angeles
European journal of biochemistry 2000 v.267 no.24 pp. 7209-7217
adipocytes, adipose tissue, genes, glycerol-3-phosphate dehydrogenase, humans, promoter regions, rats, transcription (genetics), transcription factors, transfection
We report data on the structural and functional characterization of the 5′ flanking region of the human mitochondrial glycerol‐3‐phosphate dehydrogenase (mtGPDH) gene. We found two regions upstream of 5′‐untranslated sequences exhibiting promoter activity in transient transfection assays. Transcription start sites and potential regulatory sites in both promoter regions were defined. The proximal promoter was approximately sevenfold more active than the distal one in most cell lines, but it was only twice as active in a neuroblastoma cell line. These observations seem to indicate that the rate of transcription, as well as the tissue‐specific expression of the human mtGPDH gene, is the result of a combinatorial effect of transcription factors on at least two promoters. 3,5,3′‐Triiodothyronine failed to alter the transcriptional activity of human mtGPDH promoter(s) constructs in transient transfection assays. Although this finding seems to be in conflict with the reported effect of 3,5,3′‐triiodothyronine in rodents, it is consistent with our observation of 3,5,3′‐triiodothyronine stimulation of mtGPDH activity in primary cultures of rat adipocytes, but not human cultured adipocytes, suggesting distinct regulation of this gene in both species.