(A) GST pull-down assays were performed using GST-ELF3 and in vitro translated fragments of Sox9, previously reported (26). The schematic illustration below shows the fragments of Sox9 expressed by the deletion mutants, and the positive (+) or negative (−) interactions of Sox9 fragments with ELF3 are shown on the right. The C-28/I2 cells were transfected with plasmids expressing (B) ELF3, CBP, and Sox9, alone or in combination, or (C) CBP and ELF3, alone or in combination. HAT activity was measured in nuclear extracts at 24 h after transfection. ***indicates p<0.001.