Transactivation by VP16 and LZIP is severely compromised in tsBN67-derived cells expressing HCF-1ΔrepΔAD. (A) R-tsBN67-HCF-1ΔrepWT and R-tsBN67-HCF-1ΔrepΔAD cells were transiently transfected with 6xTAAT-tk-luc (500 ng) or 1xTAAT/GA-tk-luc (1 μg) reporters together with 0.1 or 1.0 μg of the VP16FL or VP16ΔC expression plasmids and assayed for luciferase activity after incubation at 39.5°C for 40 h. (B) As in A, except cells were transfected with: (Left) a CRE-luciferase reporter (CRE-luc, 500 ng) and an expression plasmid encoding LZIPN228; (Center) a Gal4-responsive reporter (5xGal4-E1B-luc reporter, 500 ng) and 500 ng of either Gal4DBD, Gal4-c-Jun, or Gal4-VP16AD; or (Right) an estrogen response element reporter (ERE-luc, 500 ng) and plasmid encoding the human estrogen receptor (ER).