Nephrology Dialysis Transplantation, Vol 13, Issue 3 580-586, Copyright © 1998 by Oxford University Press
J Yaghoobian and T Drueke
Previous studies have shown that dexamethasone enhanced the expression of
parathyroid-hormone/parathyroid-hormone-related peptide (PTH/PTHrP)
receptor mRNA in ROS 17/2.8 osteosarcoma cells. The aim of this study was
to determine whether the induction of PTH/PTHrP receptor expression in such
osteoblast-like cells is regulated at the gene level. Dexamethasone
increased the steady-state levels of PTH/PTHrP receptor mRNA twofold at 6 h
and nearly threefold at 24 h. The half-life of the PTH/PTHrP receptor mRNA,
in the presence of actinomycin D, was 6 h both in untreated and in
dexamethasone-treated cells. When measured by nuclear run-on assay, the
rate of PTH/PTHrP receptor gene transcription was increased twofold at 24
h. PTH/PTHrP receptor mRNA expression was blocked completely after 24 h of
treatment with cycloheximide. The bonding of PTH/PTHrP to their receptor
required the synthesis of new protein and was shown to be specifically
dependent on the interaction of dexamethasone with the glucocorticoid
receptor. These data indicate that the enhancing effect of dexamethasone on
PTH/PTHrP receptor expression is rapid, requires de
novo protein synthesis, and increases the transcription rate of
the PTH/PTHrP receptor gene. Key words: PTH/PTHrP
receptor; transcription; osteoblast-like cells; PTH; glucocorticoids
ORIGINAL ARTICLES
Regulation of the transcription of parathyroid-hormone/parathyroid-hormone-related peptide receptor mRNA by dexamethasone in ROS 17/2.8 osteosarcoma cells
INSERM Unite 90, Hopital Necker, 161 rue de Sevres, F-75743 Paris Cedex 15, France; Corresponding author
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