Fig. 5.

RUNX1t1 modulates C/EBPβ activity. a Immunostaining shows C/EBPβ and RUNX1t1 colocalization in the neck zone of the normal human gastric mucosa. b Flag-Immunoprecipitation after transfection of gastric cell lines with a flag-tagged RUNX1t1 pulls down C/EBPβ. Visible in the input Western blot is also that RUNX1t1 does not affect C/EBPβ expression. c EMSA using a radiolabeled C/EBPβ consensus probe shows that transfection of RUNX1t1 to gastric cancer cells reduces the binding of C/EBPβ to DNA in MKN28 and MKN45 cell lines. Arrow indicated the super-shift. Also visible in the control Western blots, RUNX1t1 has no effect on basal C/EBPβ expression. d A RUNX1t1-dependent increase in the expression of TFF1 was visible by real-time PCR in the MKN74 cell line. e Luciferase assay in MKN45 cells transfected with the TFF1-luciferase fused promoter shows that co-transfection with RUNX1t1 reverts the repressive potential of C/EBPβ on the TFF1 promoter