Fig. 4

KLF4 and YY1 regulate MICA expression. A A 535 bp MICA promoter construct with binding sites for YY1, KLF4, and CTCF was used for the reporter assays. B Dual-Luciferase® Reporter (DLR™) Assay to determine the impact of KLF4, YY1, and MLF2 on the MICA standard promoter. Equal amounts of expression vector DNA were transfected. As a control (Ctrl) an expression vector encoding GFP was used. The luciferase activity was determined according to firefly / renilla normalized to the GFP control. C HEK293 cells were transiently transfected with the KLF4 expression plasmid as a positive control, an inducible KLF4 (iKLF4) or an inducible mutant lacking the DNA-binding domain (iDN-KLF4). The expression was induced by doxycycline (dox) using the Tet-on system. Activation of the MICA reporter was measured (see B). Data are shown as the mean (± SEM) of three independent experiments. Significance was calculated using an unpaired t-test. See supplemental figure S2  for validation of the inducible KLF4 expression by Western blot