Abstract
For steroid hormone function to occur, nuclear receptors interact with a series of coactivators including steroid receptor coactivator-1 (SRC-1). The SRC-1 binds the vitamin D receptor (VDR) in the presence of ligand in an activation function 2 (AF-2)-dependent manner. In order to understand the role of this interaction in 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]-mediated gene expression, the level of SRC-1 expression was altered in MG-63 cells. Previous studies had demonstrated that MG-63 cells express the VDR and that 1,25(OH)2D3 regulates expression of alkaline phosphatase (ALP). Analysis of MG-63 cells demonstrated that SRC-1 is expressed. A full-length cDNA coding for SRC-1 was inserted in antisense orientation into an expression vector (anti-SRC-1). The MG-63 cells were transfected with anti-SRC-1 or mock vector and stable transformants were selected. Western blot analysis showed a 95% reduction in SRC-1 protein as compared with mock cells. We determined the effect of normal and reduced SRC-1 expression in MG-63 cells on 1,25(OH)2D3-mediated stimulation of ALP. Whereas 10−8 M 1,25(OH)2D3 produced a 3.6-fold stimulation in ALP in mock cells expressing normal levels of SRC-1, it did not alter ALP in cells expressing reduced levels of SRC-1. Thus, SRC-1 is required for 1,25(OH)2D3-mediated gene expression of ALP by human MG-63 cells.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 7 June 1999 / Accepted: 2 November 1999
Rights and permissions
About this article
Cite this article
Gill, R., Bell, N. Steroid Receptor Co-activator-1 Mediates 1,25-Dihydroxyvitamin D3-Stimulated Alkaline Phosphatase in Human Osteosarcoma Cells. Calcif Tissue Int 66, 370–374 (2000). https://doi.org/10.1007/s002230010075
Published:
Issue Date:
DOI: https://doi.org/10.1007/s002230010075