IRF-7 activation by MyD88 and TRAF6. HEK293T cells were cotransfected transiently with p125-Luc (50 ng) and the expression vector for the indicated combinations of MyD88 (10 ng), MyD88 mutants (10 ng), IRF-3 (0, 1, or 10 ng), IRF-7 (10 ng in b; 0, 1, or 10 ng in a and d), and TRAF6 [10 ng in b; 0, 1, 5 or 10 ng in c]. After 24 h of transfection, cells were harvested, and luciferase activity was measured.