Amplification of the exon 9 to 13 region of DMT1 mRNA from reticulocytes. (A) RNA from the patient's reticulocytes and those of a healthy control was isolated, and total cDNA was synthesized as described in “Patients, materials, and methods.” The exon 9 to 13 region of DMT1 cDNA was amplified by PCR and the PCR products were separated on a 1% agarose gel. Lane 1, 123-bp ladder; lane 2, no template control; lane 3, patient's reticulocytes; lane 4, healthy control's reticulocytes. The upper band in lanes 3 and 4 corresponds to a size of 492 bp, the lower band in lanes 3 and 4 corresponds to a size of 372 bp. (B) Schematic representation of DMT1 pre-mRNA processing in the patient and in wild-type control. (C) Amplification of the exon 9 to 13 region of DMT1 mRNA from various hematopoietic cells. RNA from the patient's reticulocytes, mononuclear cells, and CFU-GMs, and from corresponding cells from a healthy control was isolated and total cDNA was synthesized. The exon 9 to 13 region of DMT1 cDNA was amplified by PCR, and the PCR products were separated on a 1% agarose gel. Lanes 1, 3, and 5 are from a healthy control; lanes 2, 4, and 6 are from the patient. Platelets and granulocytes from the patient and healthy controls were also examined and data were similar to mononuclear cells (data not shown). (D) Amplification of the exon 9 to 13 region of DMT1 mRNA from reticulocytes and duodenum. RNA was isolated from a small sample of the patient's duodenum (obtained at endoscopy) and from the duodenum of a healthy control, and total cDNA was synthesized. The exon 9 to 13 region of DMT1 cDNA was amplified by PCR, and the PCR products were separated on a 1% agarose gel. Lanes 1 and 3 are from a healthy control; lanes 2 and 4 are from the patient.