(A) Time-response: C/EBPε mRNA expression in NB4 cells cultured with 9-cis RA. Northern blot with total RNA (30 μg/lane) of NB4 exposed for various lengths of time to 9-cis RA (5 × 10−7 mol/L) and probed with full-length C/EBPε cDNA. The bottom panel shows ethidium bromide-staining of the 28S and 18S rRNA on the gel as assessment of RNA quantities in each lane. Fold-inductions were calculated by the ratio of densitometry readings of C/EBPε to β-actin. (B) Dose-response: C/EBPε mRNA levels in NB4 cells treated with 9-cis RA. Northern blot of total RNA (30 μg/lane) of NB4 cells exposed to various concentrations of ATRA for 12 hours and hybridized with full-length C/EBPε cDNA probe. The bottom panel shows hybridization with the β-actin probe as assessment of RNA quantities in each lane. Fold-inductions were calculated by the ratio of densitometry readings of C/EBPε to β-actin.
