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Two nuclear signalling pathways for vitamin D
1Department of Pharma Research New Technologies, F. Hoffmann-La Roche Ltd, Basel, Switzerland.
Nature
|February 18, 1993
Summary
Vitamin D3
Area of Science:
- Molecular Biology
- Endocrinology
- Genetics
Background:
- Vitamin D3's active form, 1,25-dihydroxy-D3, regulates gene expression via intracellular receptors.
- These receptors are part of the steroid receptor superfamily and function as ligand-dependent transcription factors.
Purpose of the Study:
- To identify and characterize distinct classes of vitamin D response elements (VDREs).
- To investigate the roles of the vitamin D receptor (VDR) and retinoid-X receptor-alpha (RXR-alpha) in regulating gene transcription.
Main Methods:
- Analysis of DNA sequences conferring vitamin D inducibility.
- Identification of motifs recognized by VDR alone and by VDR-RXR-alpha heterodimers.
Main Results:
- Two classes of VDREs were identified: one activated by VDR alone, the other synergistically by VDR and RXR-alpha.
- Specific DNA motifs and spacing patterns were associated with each class of response element.
- Co-regulation by RXR depends on the presence of its ligand and the specific response element sequence.
Conclusions:
- The nature of the response element and the presence of RXR ligands dictate nuclear receptor co-regulation.
- This provides a deeper understanding of vitamin D and retinoid signaling pathways.