title: Development of Erythroid Progenitors under Erythropoietin Stimulation in Xenopus laevis Larval Liver.
abstract: Erythroid progenitors that respond to erythropoietin (Epo) are present in the liver of adult Xenopus laevis. However, cells responding to Epo in the larval liver and through the metamorphosis period under hepatic remodeling have not been characterized. In this study, tadpoles were staged using the tables of Nieuwkoop and Faber (NF). Liver cells from pre- (NF56) or post- (NF66) metamorphic stage were cultured in the presence of Epo. β2-globin mRNA expression peaked at day 7 after the start of culture. Larval β2-globin was highly expressed in NF56-derived cells, while adult β2-globinwas detected in those of NF66. In both NF56- and NF66-derived cells, mRNA expression of eporand gata2 peaked at day 5 and days 3-4, respectively. In contrast, gata1 expression peaked at day 6 in NF56 cells and at day 5 in NF66 cells. Half maximal proliferation of erythrocytic blast cells derived from the liver at NF66 was observed at day 3, which was earlier than that of NF56. These results indicate that erythroid progenitors that respond to Xenopus laevis Epo are maintained in pre- and post-metamorphic liver, although the tissue architecture changes dramatically during metamorphosis. Additionally, the globin switching occurred, and/or the erythroid progenitors for larval erythrocytes were replaced by those for adult erythrocytes in the metamorphic liver.
authors.affiliation: 1 Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Center for Advanced Life and Medical Science, Waseda University, TWIns Building, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Takehito
authors.initials: T
authors.lastname: Okui
authors.affiliation: 1 Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Center for Advanced Life and Medical Science, Waseda University, TWIns Building, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Sakiko
authors.initials: S
authors.lastname: Hosozawa
authors.affiliation: 1 Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Center for Advanced Life and Medical Science, Waseda University, TWIns Building, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Satoka
authors.initials: S
authors.lastname: Kohama
authors.affiliation: 1 Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Center for Advanced Life and Medical Science, Waseda University, TWIns Building, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Fujiyama
authors.affiliation: 2 Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, TWIns Building, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Shun
authors.initials: S
authors.lastname: Maekawa
authors.affiliation: 1 Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Center for Advanced Life and Medical Science, Waseda University, TWIns Building, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Muto
authors.affiliation: 1 Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Center for Advanced Life and Medical Science, Waseda University, TWIns Building, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.|2 Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, TWIns Building, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
mesh_terms: D000818:Animals; D015672:Erythroid Precursor Cells / Q000378:metabolism; D004920:Erythropoiesis; D004921:Erythropoietin / Q000494:pharmacology*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007814:Larva; D008099:Liver / Q000196:embryology* / Q000378:metabolism*; D014981:Xenopus / Q000196:embryology*
chemical_list: D004921:Erythropoietin
keywords: African clawed frog; erythropoiesis; erythropoietin; hematopoiesis; liver; metamorphosis; tadpole