MEF-2-associated signaling pathways are triggered during HTLV-1 infection. (A) A protein-DNA array was used to determine the activation of the various eukaryotic transcription factors. Nuclear extracts from control and HTLV-infected primary cells were mixed with biotinylated DNA binding oligonucleotides for the formation of protein-DNA complexes. These probes were then hybridized to pretreated array membranes and the bound probe was detected as described in Methods. Densitometric analysis was used to quantify the spots and data was normalized to their respective controls after background subtraction. Fold change in expression of selected transcription factors from the array data compared to relevant uninfected cells. Significance was determined using the Student’s t-test (*P ≤ 0.05). (B) Cells were lysed and Western blotting was performed to confirm the array data.