Northern blot analysis of NB4 cells treated with ATRA

. RNA (10 μg) isolated from uninduced (0) and ATRA-induced (24, 48, 72 h) NB4 cells were subjected to Northern blot analysis. The blot was sequentially probed with ³²P-labeled cDNA probes for HNP, gp91phox, and LF as described in “Materials and methods.” Equal loading of RNA in each lane was determined by the presence of an equal concentration of both 18S and 28S ribosomal RNA in each lane in the ethidium bromide stained gel prior to blotting (bottom panel).