Figure 5.

Transactivation of a RARE through combinations of the RXRα, RARα1 and RARα1ΔBC receptors upon binding to the retinoids ATRA (white bars), RAR agonist CD336 (red bars) or RXR agonist CD2809 (green bars). RARα1ΔBC alone does not produce significant activity of the RARE₃-tk-luc reporter in COS cells (lane 4); the RXRα/RARα1ΔBC heterodimers transactivate a RARE upon binding to ATRA, CD336 or CD2809 (lane 7); RXRα/RARα1 transduces the transactivating signal mediated by ATRA and CD336 (lane 5); RARα1 fixation inhibits the transactivation mediated by CD2809 binding to RXRα (lanes 5 and 3, green bars, respectively). Luciferase activities were normalized to β-galactosidase activities. A representative experiment, done in triplicate, is shown. All the retinoids were used at 10^–6 M. The results are expressed as fold induction produced by the transfected receptors related to pSG5 empty vector in the presence of ATRA.