Regulation of C/EBPε expression in NB4 cells induced to differentiate after ATRA-priming. Northern blot of total RNA (30 μg/lane) from NB4 cells treated with various differentiating agents for 3 days with or without 30 minutes of priming with 1 × 10⁻⁷ mol/L ATRA. The top panel shows the hybridization of full-length C/EBPε cDNA probe. The bottom panel shows the hybridization with the β-actin probe as assessment of RNA quantities on each lane.