RNA blot analysis of DMT1 expression in duodenum of HFE+/+ and HFE−/− mice. Poly(A)+ RNA (3 μg, lanes 1–4; 10 μg, lanes 5–6) from duodenum of a 4-week-old HFE+/+ mouse (lanes 1, 3, and 5) and a HFE−/− littermate (lanes 2, 4, and 6) were electrophoresed in triplicate and blotted. Lanes 1 and 2 were hybridized with a 32P-labeled coding-sequence probe [DMT1(total)] to detect all DMT1 transcripts. Lanes 3 and 4 were hybridized with an oligonucleotide probe [DMT1(IRE)] specific to DMT1 transcripts with an IRE, and lanes 5 and 6 were hybridized with an oligonucleotide probe [DMT1(non-IRE)] specific to the DMT1 splice-variant transcripts without an IRE. Blots were exposed to film for 18 h (lanes 1–4) or 48 h (lanes 5 and 6) with an intensifying screen, and rehybridized with a probe for GAPDH. Positions of RNA size markers are on the left.