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Updated: May 16, 2026

Isolation of Mesenchymal Stem Cells from Human Alveolar Periosteum and Effects of Vitamin D on Osteogenic Activity of Periosteum-derived Cells
Published on: May 4, 2018
Vitamin D directly regulates Mdm2 gene expression in osteoblasts
Hankui Chen1, Grant Reed, Janete Guardia
1Department of Biochemistry, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, United States.
1,25-dihydroxy vitamin D3 activates Mdm2 gene expression via the P2 promoter in MC3T3 cells. This vitamin D receptor-mediated upregulation of Mdm2 requires the tumor suppressor p53.
Area of Science:
- Molecular Biology
- Cell Biology
- Endocrinology
Background:
- Mdm2 negatively regulates the p53 tumor suppressor.
- Mdm2 also has p53-independent roles in cellular differentiation.
- Mdm2 gene expression is controlled by two promoters: P1 and P2.
Purpose of the Study:
- To investigate the effect of 1,25-dihydroxy vitamin D3 on Mdm2 gene expression.
- To determine the role of the P1 and P2 promoters in vitamin D-mediated Mdm2 regulation.
- To elucidate the involvement of p53 in vitamin D's regulation of Mdm2.
Main Methods:
- Utilized P1 and P2-specific reporter assays in MC3T3 cells.
- Identified a vitamin D receptor responsive element in the Mdm2 P2 promoter.
- Employed p53-temperature sensitive and p53-null cell lines.
Main Results:
- 1,25-dihydroxy vitamin D3 specifically activates P2-initiated Mdm2 transcription.
- A potential vitamin D receptor responsive element was found near p53 response elements in the P2 promoter.
- p53 is essential for the vitamin D receptor-mediated upregulation of Mdm2 expression.
Conclusions:
- 1,25-dihydroxy vitamin D3 and its receptor regulate P2-initiated Mdm2 gene expression.
- This regulation occurs in a p53-dependent manner.
- Vitamin D signaling impacts Mdm2 expression through p53-dependent pathways.
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