Fig. 8.

P-TEFb Is Not Involved in HEXIM1-Mediated Suppression of Glucocorticoid Responsiveness

A, HeLa cells were transfected with 3 μg of empty vector or expression plasmids for the indicated HA-tagged mutant HEXIM1. Cells were infected 4 h later with AdsiHEXIM1 in phenol red-free Opti-MEM I at MOI of 100 for 36 h, and treated with vehicle or 10 nm 3MC (top panel), or 100 nm DEX (middle and bottom panels) for 6 h. Endogenous mRNA levels for cyp1a1, atp1a1, scnn1a, and gapdh were measured with qRT-PCR. Samples were normalized to gapdh mRNA, and mRNA induction levels by cognate ligands are shown in fold induction. Error bars represent sd values of at least three independent experiments. B, HepG2 cells were infected with FLAG-GR-expressing adenovirus (MOI of 50) along with LacZ- or mutant HEXIM1-expressing adenoviruses (MOI of 40) in phenol red-free Opti-MEM I for 24 h, and the cells were treated with 1 μm DEX for 20 min. ChIP assays were performed with polyclonal anti-GR antibodies as described in Materials and Methods. Error bars represent sd values of at least three independent experiments. IP, Immunoprecipitation.