MEF-2 physically interacts with Tax. (A) Control (Jurkat), infected (MT-2) cell lines, control primary CD4+ T cells and HTLV-infected primary CD4+ T cells were lysed, sonicated and protein concentration was determined by Bradford assay. Equal protein quantities were then resolved by SDS-PAGE and transferred to PVDF membrane. Following a 1 hr block membranes were incubated with antibodies against the transcription factors. Western blot shows the expression of transcription factors in control and infected cell lines and primary cells. (B) MEF-2 complex formation with Tax and transcription factors was analyzed using an immunoprecipitation assay. Cells were lysed using an immunoprecipitation lysis buffer and then incubated with MEF-2 antibody overnight at 4°C as described in Methods. Western immunoblot analysis was performed to confirm immunoprecipitation. (C) Control and infected cell lines and primary cells were enriched for Tax and immunoblotted to determine complex formation with MEF-2 and transcription factors. Data is representative of multiple individual experiments.