Figure 3.

CBP augments Arm transcriptional activity in a context-dependent manner. (A) 293 HEK cells were transfected with plasmids expressing an activated form of Arm (Arm^*; 20 ng) and fly CBP (200 or 400 ng) along with the Topflash luciferase reporter. CBP increases Arm activation of the Wnt reporter. (B) Fly Kc cells were transfected with Arm^* (20 ng) and CBP (50, 100, 200 or 400 ng) expression constructs along with the Dropflash luciferase reporter gene. CBP had a slight inhibitory effect on the ability of Arm^* to activate the Wg reporter. (C–E) Kc cells transfected with plasmids (20 ng) expressing the Gal4-DBD domain alone or Gal4-DBD fused to full-length Arm (Gal4-Arm), the N-terminal half of Arm (Gal4-ArmN; residues 1–428) or the C-terminal half of Arm (Gal4-ArmC; residues 429–815). CBP or CBP^Hatmut constructs were transfected as indicated at 20 or 50 ng. The Gal4 UAS-luciferase (UAS-luc) reporter gene was activated by Gal4-Arm, Gal4-ArmN and Gal4-ArmC, and CBP coexpression augmented this activation for Gal4-Arm and Gal4-ArmC but not Gal4-ArmN. CBP^HATmut did not effect Gal4-ArmC activation of UAS-luc. All transfections contained a lacZ expression plasmid, and luciferase activities were determined 48 h post-transfection and normalized against β-galactosidase activity. Values are the mean of duplicate experiments (standard deviations are indicated) and expressed as relative activity compared with cells transfected with the reporter alone.