The 1£\, 25-dihydroxyvitamin D3 (1,25(OH)2D3) is involved in various physiological processes, including calcium/phosphorous homeostasis, cell growth, differentiation and apoptosis. 1,25(OH)2D3 induces the formation of VDR/RXR complex to up-regulate or down-regulate target gene expression. Recent studies find that VDR undergoes several post-translational modifications, such as phosphorylation and ubiquitination, which may regulate its transcriptional activity and/or stability. In this study, we identified VDR as a new target for small ubiquitin-related modifier (SUMO)-2 modification in vitro. In E. coli. SUMO-conjugation system, VDR is mainly sumoylated at Lys-103. SUMOylation of VDR enhanced VDR/RXR-mediated transcriptional activation as determined by promoter activity assay. In addition, 1,25(OH)2D3-induced expression of osteopontin was attenuated after mutation of VDR SUMOylation site. However, chromatin immunoprecipitation assay indicated that wild type and K103A mutant of VDR bound to the osteopontin promoter with similar affinity. Collectivity, our results suggest that SUMOylation of VDR may affect its transcriptional activity by modulating the interaction between VDR and co-activators.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0720106-183555 |
| Date | 20 July 2006 |
| Creators | Tsai, Nian-gui |
| Contributors | Wen-chun Hung, none, none, Long-sheng Chang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0720106-183555 |
| Rights | withheld, Copyright information available at source archive |
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