FIG. 5.

NFI and TTF-1 fusion proteins interact via the conserved 5′ DNA binding and dimerization domain (dbd) of NFI. JEG cells were cotransfected with the indicated combinations of vectors expressing fusion proteins of the GAL dbd and the VP16 transactivation domain (tad), a luciferase reporter plasmid driven by the GAL4 upstream activator sequences, and pCMVβgal as an internal control. Relative luciferase activity was calculated as described for Fig. 1 except that luciferase activity stimulated by each GALdbd fusion protein (full-length TTF-1, NFI-A1, or NFI-A5′dbd) cotransfected with the VP16tad vector pM (control) was set to 1. Data are plotted as means ± SE (n = 6).