BATF3 is a context-specific co-activator of GR.

<p>(a) U2OS cells were cotransfected with an expression construct for GRα, a luciferase reporter encompassing a minimal promoter and a ~1kb GR region derived from the GR-responsive <i>GILZ</i> gene and increasing amounts of an expression construct for FLAG-tagged BATF3. Average normalized luciferase activity ± S.E.M. (n = 3) is shown for cells treated overnight with either 1 μM dexamethasone (dex) or ethanol (-) as vehicle control. (b, top) Same as for (a) except that a different luciferase reporter containing a minimal promoter and the CGT GBS was used. (b, bottom) Western blot analysis of dexamethasone-treated cells transfected with increasing amounts of FLAG-tagged BATF3 expression construct. Expression of FLAG-tagged BATF3 and actin (loading control) are shown. (c) U2OS cells stably expressing comparable amounts of either GRα or GRγ were transfected with the CGT luciferase reporter and increasing amounts of FLAG-tagged BATF3 expression construct. Average normalized luciferase activity ± S.E.M. (n = 3) is shown for cells treated overnight with either 1 μM dexamethasone (dex) or ethanol (-) as vehicle control. The p-values were calculated using a two-tailed Student’s t-test. (d) Western blot analysis of cells U2OS cells stably expressing comparable amounts of either GRα or GRγ that were transfected as described for with 15ng FLAG-tagged BATF3 expression construct and treated overnight with either 1 μM dexamethasone (+) or ethanol (-) as vehicle control. Expression of GR, FLAG-tagged BATF3 and actin (loading control) are shown.