Western blot analysis of the ATRA effect on the expression levels of RARα, RARβ, and RARγ in KG-1 cells. Nuclear extracts were made from KG-1 cells, which were treated with ATRA (1 μM) or TPA (0.05 μM) for 5 days and subjected to Western blot analysis as described in “Materials and methods.” In each lane, 10 μg protein (for RARα) or 20 μg protein (for RARβ and RARγ) was loaded, and the blots were probed with antibody specific for RARα, RARβ,orRARγ.