Expression of erythropoietin receptor-like molecule in Xenopus laevis and erythrocytopenia upon administration of its recombinant soluble form
Expression of erythropoietin receptor-like molecule in Xenopus laevis and erythrocytopenia upon administration of its recombinant soluble form
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DOI：
10.1093/jb/mvi113
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发表时间：
2005-08-01
影响因子：
2.7
通讯作者：
Kato, T
中科院分区：
文献类型：
--
作者：
Aizawa, Y;Nogawa, N;Kato, T
对非哺乳类脊椎动物造血的调控知之甚少。这部分是因为大多数造血调节因子的结构和作用尚未确定。作为对造血调控的关键机制在门之间的研究以及生物多样性的第一步，我们集中在两栖动物造血。从非洲爪蟾（Xenopus laevis）未成熟红细胞cDNA文库中克隆了一个与哺乳动物促红细胞生成素（EPO）受体同源性最高的cDNA，暂命名为xlEPOR。推导的整个氨基酸序列的哺乳动物EPO受体的比较身份是相当低的，虽然红细胞生成活动不可缺少的功能域中发现的分子。北方分析显示xlEPOR在外周血细胞中表达。在苯肼处理的成年非洲爪蟾外周血中，通过原位杂交和用xlEPOR多克隆抗体进行免疫染色来鉴定表达xlEPOR的未成熟红细胞。为了证实该分子的生物学功能，xlEPOR的胞外结构域（即，可溶性xlEPOR）通过连续心内注射给予成年非洲爪蟾。外周血红细胞计数逐渐减少，同时循环中出现未成熟红细胞，表明xlEPOR在非洲爪蟾红细胞生成中起重要的生理作用。
The regulation of hematopoiesis in non-mammalian vertebrates is poorly understood. This is partly because the structures and effects of most hematopoietic regulators have not been identified. As a first step towards studies on the key mechanism of hematopoietic regulation among phyla as well as the diversity of organisms, we have focused on amphibian hematopoiesis. A cDNA sharing the highest degree of homology with mammalian erythropoietin (EPO) receptors, tentatively named xlEPOR, was cloned from a cDNA library of Xenopus laevis immature erythrocytes. The comparative identities of the deduced entire amino acid sequence to mammalian EPO receptors were quite low, although functional domains indispensable for erythropoietic activities were found in the molecule. Northern analysis revealed that xlEPOR were expressed in peripheral blood cells. In the peripheral blood of phenylhydrazinetreated adult Xenopus, immature erythrocytes expressing xlEPOR were identified by in situ hybridization and immunostaining with polyclonal antibodies to xlEPOR. To confirm the biological functions of this molecule, the extracellular domain of xlEPOR (i.e., soluble xlEPOR) was administered to adult Xenopus by consecutive intracardiac injection. The peripheral erythrocyte counts were decreased gradually; meanwhile, immature erythrocytes appeared in the circulation, demonstrating that xlEPOR plays a significant physiological role in erythropoiesis in Xenopus laevis.