Piwi positive cells that line the vasculature epithelium, underlie whole body regeneration in a basal chordate

Yuval Rinkevich, Amalia Rosner, Claudette Rabinowitz, Ziva Lapidot, Elithabeth Moiseeva, Buki Rinkevich

Research output: Contribution to journalArticlepeer-review


The colonial tunicate Botrylloides leachi can regenerate functional adults from minute vasculature fragments, in a poorly understood phenomenon termed Whole Body Regeneration (WBR). Using Piwi expression (Bl-Piwi), blood cell labeling and electron microscopy, we show that WBR develops through activation, mobilization and expansion of 'dormant' cells which normally line the internal vasculature epithelium of blood vessels. Following a mechanical insult, these cells express Bl-Piwi de novo, change morphology and invade niches of the vasculature lumen, where they proliferate and differentiate, regenerating a functional organism. Mitomycin C treatments and siRNA knockdown of Bl-Piwi result in deficient cells incapable of expanding or differentiating and to subsequent regeneration arrest. Last, we find similar transient mobilization of Piwi+ cells recurring every week, as part of normal colony development, and also during acute environmental stress. This recurrent activation of Piwi+ cells in response to developmental, physiological and environmental insults may have enabled the adaptation of colonial tunicates to the imposed varied conditions in the marine, shallow water environment.

Original languageEnglish
Pages (from-to)94-104
Number of pages11
JournalDevelopmental Biology
Issue number1
StatePublished - Sep 2010
Externally publishedYes

Bibliographical note

Funding Information:
We thank G. Paz and J. Douek for assistance in manuscript preparation. This study was supported by a grant from the Marine Genomics Europe Network of Excellence (EDD Node to BR), from the United States-Israel Bi-National Science Foundation ( 2003-010 to BR) and from the Israel Academy of Science ( 550-06 to BR). The authors declare that no competing interests exist.


  • Ascidian
  • Botrylloides leachi
  • Piwi
  • Regeneration
  • Stem cells

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology
  • Developmental Biology


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