title: Transferrin receptor 2 protein is not expressed in normal erythroid cells.
abstract: Human TFR2 (transferrin receptor 2) is a membrane-bound protein homologous with TFR1. High levels of TFR2 mRNA were found mainly in the liver and, to a lesser extent, in erythroid precursors. However, although the presence of the TFR2 protein in hepatic cells has been confirmed in several studies, evidence is lacking about the presence of the TFR2 protein in normal erythroid cells. Using two anti-TFR2 monoclonal antibodies, G/14C2 and G/14E8, we have provided evidence that TFR2 protein is not expressed in normal erythroid cells at any stage of differentiation, from undifferentiated CD34+ cells to mature orthochromatic erythroblasts. In contrast, erythroleukaemic cells (K562 cells) exhibited a high level of expression of TFR2 at both the mRNA and the protein level. We can therefore conclude that an elevated expression of TFR2 protein is observed in leukaemic cells, but not in normal erythroblasts. The implications of this observation for the understanding of the phenotypic features of haemochromatosis due to mutation of the TFR2 gene are discussed.
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Calzolari
authors.forename: Silvia
authors.initials: S
authors.lastname: Deaglio
authors.forename: Nadia Maria
authors.initials: NM
authors.lastname: Sposi
authors.forename: Eleonora
authors.initials: E
authors.lastname: Petrucci
authors.forename: Ornella
authors.initials: O
authors.lastname: Morsilli
authors.forename: Marco
authors.initials: M
authors.lastname: Gabbianelli
authors.forename: Fabio
authors.initials: F
authors.lastname: Malavasi
authors.forename: Cesare
authors.initials: C
authors.lastname: Peschle
authors.forename: Ugo
authors.initials: U
authors.lastname: Testa
mesh_terms: D000906:Antibodies / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000473:pathology; D002460:Cell Line; D045744:Cell Line, Tumor; D041905:Erythroid Cells / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D015672:Erythroid Precursor Cells / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D008113:Liver Neoplasms / Q000235:genetics / Q000473:pathology; D008970:Molecular Weight; D020033:Protein Isoforms / Q000096:biosynthesis / Q000737:chemistry / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis; D011990:Receptors, Transferrin / Q000096:biosynthesis* / Q000737:chemistry / Q000276:immunology; D013347:Subcellular Fractions / Q000737:chemistry
chemical_list: D000906:Antibodies; D020033:Protein Isoforms; D012333:RNA, Messenger; D011990:Receptors, Transferrin; C503640:TFR2 protein, human