Localization of a Negative Vitamin D Response Sequence in the Human Growth Hormone Gene

• Published in: Biochemical and biophysical research communications 2002-03, Vol.292 (1), p.250-255
• Main Authors: Seoane, Samuel, Alonso, Manuela, Segura, Carmen, Pérez-Fernández, Román
• Format: Article
• Language: English
• Subjects: 1,25(OH)2 D3; Base Sequence; Calcitriol - pharmacology; Electrophoretic Mobility Shift Assay; Gene Silencing; Glutathione Transferase - genetics; hGH; Human Growth Hormone - genetics; Humans; MCF-7; Molecular Sequence Data; Promoter Regions, Genetic; Receptors, Calcitriol - genetics; Receptors, Calcitriol - metabolism; Recombinant Fusion Proteins - metabolism; Sequence Deletion; Tumor Cells, Cultured; VDR; vitamin D; Vitamin D Response Element
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.2002.6641

1,25-Dihydroxyvitamin D3 [1,25(OH)2 D3] exerts its biological effects by binding to the vitamin D receptor (VDR), which binds in turn to the vitamin D response elements located in the target gene's promoter. We have previously demonstrated that VDR binds in vitro with high affinity to the 5′-flanking sequence of the human growth hormone (hGH) gene. In this study, we analyzed the response to 1,25(OH)2 D3 of hGH-promoter constructs introduced by transfection into the MCF-7 human adenocarcinoma cell line. We found that the transcriptional activity of some of these constructs was markedly reduced by 1,25(OH)2 D3. Deletion analyses revealed that a 34-bp sequence located between positions −62 and −29 upstream of the transcription start site is sufficient for this repressive response. This conclusion was also confirmed by gel mobility shift assays. Our results indicate that vitamin D inhibits hGH gene transcription, directly or by interference with other transcription factors.