Figure 3. BATF-mediated regulation of AP-1 activity in RPMI8226 cells. (A) Overexpression of BATF reduces AP-1 activity in RPMI8226 and 293T cells. Cells were transiently transfected with reporter plasmids and expression plasmids, and treated with YG32. AP-1 activity was measured using a luciferase assay. Luciferase activity in cells co-transfected with pcDNA3.1-BATF is shown relative to that in cells co-transfected with pCDNA3.1 (set to 1). (B) Expression of BATF in RPMI8226 cells was reduced by siRNA treatment. Expression of BATF was measured using real-time PCR at 2 days after electroporation of siRNA oligonucleotides. (C) BATF knockdown reverses the reduction in AP-1 activity upon CD99 engagement. Cells were transfected with reporter plasmids 2 days after electroporation with siRNA oligonucleotides. Luciferase activities were normalized with respect to -galactosidase activities. The values show this normalized activity in Ab-treated cells relative to that in cells treated with control IgG. The error bars indicate the SD of three independent experiments.