FIG. 2.

Direct interaction between h-mtTFB1 or h-mtTFB2 and h-mtTFA requires the C-terminal activation domain of h-mtTFA. The results of solid-phase protein-protein interaction assays are shown. (A) The amount of recombinant gel-purified h-mtTFA that remained stably associated with a GST::h-mtTFB1 fusion protein that was bound to glutathione-Sepharose beads was visualized by Western immunoblotting with an antibody to h-mtTFA (lanes labeled as “bound h-mtTFA”). Full-length h-mtTFA (indicated as such) as well as the following three C-terminal deletion mutants was analyzed: 1-199 (missing C-terminal 5 amino acids), 1-194 (missing C-terminal 10 amino acids), and 1-179 (missing entire C-terminal 25-amino-acid tail). Twenty-five percent of the total amount of protein initially incubated with the beads in each assay is also shown (indicated as “input h-mtTFA”). (B) The results of a direct protein-binding assay between h-mtTFB2 and h-mtTFA C-terminal deletion mutants are shown in the same manner as described for panel A above.