FIG. 2.

A) Transactivation of hGRα, hGRβ, and hGRα truncation mutants. The hGRα proteins described in Fig. 1C were analyzed for transactivation potential following transient transfection in GR-deficient COS-1 cells. Cells were cotransfected with the indicated GR expression vector and a glucocorticoid-responsive MMTV-CAT reporter gene (pGMCS). Hormone response was measured as the fold induction of CAT activity in response to 100 nM Dex treatment (DEX, hatched bars) over that of untreated cells (CON, solid bars). Data are an average from two experiments with the indicated standard error of the mean. Protein expression levels, determined by Western blotting for each condition, are shown beneath the graph. (B) Dominant negative activities of hGRβ and the three-hGRα truncation mutants. Dominant negative activity is measured as the decrease in hormone response (fold induction) upon coexpression of hGRα with 10-fold more of the empty vector (pCMV5 [CMV]), hGRβ, or the other hGRα truncation mutants. The percentage of transactivation is shown in parentheses above each bar, where hGRα plus the empty pCMV5 vector is 100%. The relative amounts of transfected expression vectors are indicated below the graph. Transfection and CAT assays were carried out as for panel A. Data shown are an average for four to seven experiments with the indicated standard error of the mean.