Calzolari Alessia, Deaglio Silvia, Sposi Nadia Maria, Petrucci Eleonora, Morsilli Ornella, Gabbianelli Marco, Malavasi Fabio, Peschle Cesare, Testa Ugo
Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
Biochem J. 2004 Aug 1;381(Pt 3):629-34. doi: 10.1042/BJ20040230.
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.
人转铁蛋白受体2（TFR2）是一种与TFR1同源的膜结合蛋白。TFR2 mRNA的高水平主要在肝脏中发现，在红系前体细胞中含量较少。然而，尽管多项研究已证实肝细胞中存在TFR2蛋白，但正常红系细胞中是否存在TFR2蛋白仍缺乏证据。使用两种抗TFR2单克隆抗体G/14C2和G/14E8，我们提供了证据表明，在从未分化的CD34+细胞到成熟正染红细胞的任何分化阶段，正常红系细胞中均不表达TFR2蛋白。相反，红白血病细胞（K562细胞）在mRNA和蛋白水平均表现出高水平的TFR2表达。因此，我们可以得出结论，白血病细胞中观察到TFR2蛋白表达升高，但正常成红细胞中未观察到。本文讨论了这一观察结果对理解TFR2基因突变导致的血色素沉着症表型特征的意义。
