Development Genes and Evolution

, Volume 215, Issue 3, pp 143–157 | Cite as

Distribution of the stem cells (neoblasts) in the planarian Dugesia japonica

  • Hidefumi Orii
  • Takashige Sakurai
  • Kenji Watanabe
Original Article


It has been postulated that the high regeneration ability of planarians is supported by totipotent stem cells, called neoblasts. There have been a few reports showing the distribution of neoblasts in planarians. However, the findings were not completely consistent. To determine the distribution of neoblasts, we focused on proliferating cell nuclear antigen (PCNA), which is present in proliferative cells. We cloned and sequenced the cDNA of PCNA from the planarian Dugesia japonica and produced an antiserum recognizing the gene product. X-ray irradiation caused rapid loss of all PCNA-positive cells and loss of the neoblasts (which were morphologically defined by the presence of the chromatoid body), strongly suggesting that all PCNA-positive cells were true neoblasts. Using the antiserum, we were successful in identifying the neoblasts more clearly than any previous work. In addition to their dispersed distribution in the dorsal and ventral mesenchyme, the neoblasts were distributed as clusters along the midline and bilateral lines in the dorsal mesenchyme. We also examined the behavior of the neoblasts after decapitation. Decapitation did not seem to affect the migration of neoblasts far from the wound. We demonstrated here that DjPCNA is a powerful tool for identifying planarian neoblasts.


PCNA Flatworm Platyhelminthes Cell proliferation Mitosis 



We are grateful to S. Hata (Kyoto University) for his generous gift of a set of degenerate primers for PCNA, M. Saitoh (Department of Radiology, Fukushima Medical College) for X-ray irradiation, Y. Kashino (Laboratory of Cell Structure at our institute) for western blotting, and I. Hori (Kanazawa Medical University) for immunoelectron microscopic studies. We also thank K. Agata, A. Tazaki, N. Shibata, K. Sato, K. Kato and Y. Saito (in our laboratory during the study period) for their support and technical advice, and K. Okaichi (Nagasaki University) for sharing his knowledge about irradiation effects. This work was supported in part by a grant from the National Institute of Agrobiological Sciences (Bio Design Program) to H.O.


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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Hidefumi Orii
    • 1
  • Takashige Sakurai
    • 2
  • Kenji Watanabe
    • 1
  1. 1.Laboratory of Regeneration Biology, Department of Life ScienceUniversity of Hyogo (Formerly: Himeji Institute of Technology)HyogoJapan
  2. 2.Fukushima Biomedical Institute of Environmental and Neoplastic DiseasesFukushimaJapan

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