Transferrin receptor 2 protein is not expressed in normal erythroid cells.
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.
Calzolari
Alessia
A
Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
Deaglio
Silvia
S
Sposi
Nadia Maria
NM
Petrucci
Eleonora
E
Morsilli
Ornella
O
Gabbianelli
Marco
M
Malavasi
Fabio
F
Peschle
Cesare
C
Testa
Ugo
U
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
D000906:Antibodies; D020033:Protein Isoforms; D012333:RNA, Messenger; D011990:Receptors, Transferrin; C503640:TFR2 protein, human