Dong Y J, Goldwasser E
Department of Biochemistry and Molecular Biology, University of Chicago, IL 60637.
Exp Hematol. 1993 Mar;21(3):483-6.
Evidence for an accessory component that can modify the affinity of the erythropoietin (Epo) receptor is presented. Dihydrofolate reductase (DHFR)-deficient Chinese hamster ovary (CHO) cells were transfected with a plasmid containing the Epo receptor cDNA (derived from murine erythroleukemia cells with only low affinity receptors) and DHFR cDNA. The cells expressed both high and low affinity receptors. Upon amplification with methotrexate (MTX), only the number of low affinity receptors increased, suggesting that there was a constitutively expressed cellular component in CHO cells that can increase Epo receptor affinity. Further support for this hypothesis was provided by our finding that fusion of IW 201 cells, which have only low affinity receptors, with nontransfected CHO cells, which have no Epo receptors, resulted in high affinity binding sites for Epo.
本文提供了一种可改变促红细胞生成素（Epo）受体亲和力的辅助成分的证据。用含有Epo受体cDNA（源自仅具有低亲和力受体的小鼠红白血病细胞）和二氢叶酸还原酶（DHFR）cDNA的质粒转染缺乏DHFR的中国仓鼠卵巢（CHO）细胞。这些细胞表达了高亲和力和低亲和力受体。在用甲氨蝶呤（MTX）扩增后，只有低亲和力受体的数量增加，这表明CHO细胞中存在一种组成性表达的细胞成分，它可以增加Epo受体的亲和力。我们发现，仅具有低亲和力受体的IW 201细胞与没有Epo受体的未转染CHO细胞融合，产生了Epo的高亲和力结合位点，这为该假说提供了进一步支持。
