Fig 9.

In vivo interactions between GAL4-AD1+2 and PC4 analyzed by transcriptional interference assays. (A) Schematic of PC4 constructs. (B) Test for inhibition of GAL4-AD1+2 activity by coexpression of PC4 mutant proteins. Effector plasmids consisted of the GAL4-AD1+2 fusion in vector pNG-SB and PC4 with the T7-tag and nuclear localization signal in vector pT7-NLS. The luciferase reporter plasmid was pG5luc, and DNA from pCI-neo served as the empty-vector control (lane C). Lane numbers correspond to construct designations. Cotransfected DNAs: 0.3 μg of GAL4-AD1+2, 3 μg of PC4 mutants, 2 μg of luciferase reporter (pG5luc), and 0.5 μg of growth hormone reporter (pXGH5). The luciferase activity of each transfection was normalized by human growth hormone expression. (C) Western blot of PC4 protein expression. The PC4 mutant proteins were transiently expressed in HeLa cells and detected with anti-T7 tag antibody