FIG. 4.

The regulation of mRNA stability by dexamethasone is dose dependent. Transfections and RNase protection assays were performed as described in the legend to Fig 2, using the reporter construct pTetBBB-Cox2.5. Dexamethasone (Dex) was added 22 h after the transfection, and tetracycline (Tet) was added after a further 2 h. (A) Representative experiment. Only the β-globin reporter and GAPDH loading control are shown. (B) Graphical representation of the experiment in panel A. Each transfection was performed at least twice, with qualitatively identical results. (C) Approximate half-lives of β-globin–Cox2.5 reporter mRNA in the presence of different concentrations of dexamethasone.