title: Identification of erythroid progenitors induced by erythropoietic activity in Xenopus laevis.
abstract: Oxygen is essential for the survival of animals. Red blood cells in the circulation, i.e. peripheral erythrocytes, are responsible for transporting oxygen to tissues. The regulation of erythropoiesis in vertebrates other than mammals is yet to be elucidated. Recently we identified erythropoietin, a primary regulator of erythropoiesis, in Xenopus laevis, which should enable us to identify target cells, including erythroid progenitors, and to investigate the production and development of erythroid cells in amphibians. Here, we established a semi-solid colony-forming assay in Xenopus laevis to clarify the existence of colony-forming unit-erythroid cells, the functional erythroid progenitors identified in vitro. Using this assay, we showed that recombinant xlEPO induces erythroid colony formation in vitro and detected an increased level of erythropoietin activity in blood serum during acute anemic stress. In addition, our study demonstrated the possible presence of multiple, non-xlEPO, factors in anemic serum supportive of erythroid colony formation. These results indicate that erythropoiesis mediated by erythropoietin is present in amphibian species and, furthermore, that the regulatory mechanisms controlling peripheral erythrocyte number may vary among vertebrates.
authors.affiliation: Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu, Shinjuku, Tokyo, Japan.
authors.forename: Nami
authors.initials: N
authors.lastname: Nogawa-Kosaka
authors.forename: Tatsuhisa
authors.initials: T
authors.lastname: Sugai
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Nagasawa
authors.forename: Yuta
authors.initials: Y
authors.lastname: Tanizaki
authors.forename: Mizue
authors.initials: M
authors.lastname: Meguro
authors.forename: Youichi
authors.initials: Y
authors.lastname: Aizawa
authors.forename: Shun
authors.initials: S
authors.lastname: Maekawa
authors.forename: Motoyasu
authors.initials: M
authors.lastname: Adachi
authors.forename: Ryota
authors.initials: R
authors.lastname: Kuroki
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
mesh_terms: D000740:Anemia / Q000097:blood; D000818:Animals; D018929:Cell Culture Techniques; D003114:Colony-Forming Units Assay; D004906:Erythrocyte Count; D015672:Erythroid Precursor Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D004920:Erythropoiesis / Q000187:drug effects*; D004921:Erythropoietin / Q000097:blood / Q000494:pharmacology*; D008099:Liver / Q000166:cytology / Q000378:metabolism; D009928:Organ Specificity / Q000187:drug effects; D017467:Receptors, Erythropoietin / Q000378:metabolism; D011994:Recombinant Proteins; D014982:Xenopus laevis / Q000097:blood / Q000378:metabolism*
chemical_list: D017467:Receptors, Erythropoietin; D011994:Recombinant Proteins; D004921:Erythropoietin