Role of the thrombopoietin (TPO)/Mpl system: c-Mpl-like molecule/TPO signaling enhances early hematopoiesis in Xenopus laevis

Minoru Kakeda, Jun Ichi Kyuno, Takashi Kato, Mitsuo Nishikawa, Makoto Asashima*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Multiple organs are induced in the primitive embryonic ectoderm excised from blastula stage Xenopus laevis embryos, under the strict control of mesoderm inducing factors. This in vitro system is useful for exploring the mechanisms of development. In this study, the function of thrombopoietin (TPO)/c-Mpl signaling in the development of hematopoietic cells was investigated. An optimal hematopoietic cell induction system was established to evaluate the influence of growth factors on hematopoiesis. It was found that exogenous TPO enhanced hematopoiesis in explants induced by activin and bone morphogenetic protein (BMP)-4 and increased the number of both erythrocytes and leukocytes in a dose-dependent manner. Addition of anti-c-Mpl antibody completely inhibited the expansion of hematopoietic cells stimulated by TPO, and the antibody specifically recognized blood-like cells. These results demonstrate that TPO acts on hematopoietic progenitors induced in explants and the c-Mpl-like molecule in Xenopus mediates the cellular function of TPO. We also found that forced expression of TPO in embryos promoted hematopoiesis in the ventral blood island and the dorsal-lateral plate mesoderm. These results suggest that hematopoietic stem and progenitor cells are regulated by TPO/c-Mpl signaling from when they appear in their ontogeny. They also suggest that TPO/c-Mpl signaling play a crucial role in the formation of hematopoietic cells in Xenopus.

Original languageEnglish
Pages (from-to)63-75
Number of pages13
JournalDevelopment Growth and Differentiation
Issue number1
Publication statusPublished - 2002
Externally publishedYes


  • Activin
  • BMP-4
  • Hematopoiesis
  • Thrombopoietin
  • Xenopus
  • c-Mpl

ASJC Scopus subject areas

  • Developmental Biology
  • Cell Biology


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