Genome-wide analysis of the VDR/RXR cistrome in osteoblast cells provides new mechanistic insight into the actions of the vitamin D hormone

MB Meyer, PD Goetsch, JW Pike - The Journal of steroid biochemistry and …, 2010 - Elsevier
The Journal of steroid biochemistry and molecular biology, 2010Elsevier
The vitamin D receptor (VDR) mediates the actions of 1, 25-dihydroxyvitamin D3 (1, 25 (OH)
2D3) in target cells and tissues by orchestrating the expression of gene networks
responsible for vitamin D-induced phenotypes. The molecular mechanisms of these
regulatory systems have been studied for decades under the principle that transcriptional
regulation occurs near the transcriptional start site of the gene. However, this now appears
to be an outdated view of transcriptional control. In this study, we examined the genome …
The vitamin D receptor (VDR) mediates the actions of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in target cells and tissues by orchestrating the expression of gene networks responsible for vitamin D-induced phenotypes. The molecular mechanisms of these regulatory systems have been studied for decades under the principle that transcriptional regulation occurs near the transcriptional start site of the gene. However, this now appears to be an outdated view of transcriptional control. In this study, we examined the genome-wide chromatin immunoprecipitation on microarray (ChIP-chip) across pre-osteoblastic cells for VDR, retinoid X receptor (RXR), RNA polymerase II, and histone H4 acetylation (H4ac). We uncovered potential regulatory mechanisms for genes important to osteoblast biology as well as skeletal formation under the control of 1,25(OH)2D3. We found that VDR, along with RXR and H4ac, binds to distal regions 43% of the time; and within gene introns and exons 44%, leaving only 13% of activation at traditional promoter regions. Here, we briefly summarize our findings for all the VDR/RXR cis-acting transcriptional elements (VDR/RXR cistrome) in pre-osteoblastic cells, MC3T3-E1, provide a few examples of this dynamic control by VDR and 1,25(OH)2D3, and demonstrate that distal transcriptional control contributes to the majority of vitamin D3-mediated transcription.
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