title: The regenerative capacity of the zebrafish caudal fin is not affected by repeated amputations.
abstract: BACKGROUND
  The zebrafish has the capacity to regenerate many tissues and organs. The caudal fin is one of the most convenient tissues to approach experimentally due to its accessibility, simple structure and fast regeneration. In this work we investigate how the regenerative capacity is affected by recurrent fin amputations and by experimental manipulations that block regeneration.
  
  
  RESULTS
  We show that consecutive repeated amputations of zebrafish caudal fin do not reduce its regeneration capacity and do not compromise any of the successive regeneration steps: wound healing, blastema formation and regenerative outgrowth. Interfering with Wnt/ß-catenin signalling using heat-shock-mediated overexpression of Dickkopf1 completely blocks fin regeneration. Notably, if these fins were re-amputated at the non-inhibitory temperature, the regenerated caudal fin reached the original length, even after several rounds of consecutive Wnt/ß-catenin signalling inhibition and re-amputation.
  
  
  CONCLUSIONS
  We show that the caudal fin has an almost unlimited capacity to regenerate. Even after inhibition of regeneration caused by the loss of Wnt/ß-catenin signalling, a new amputation resets the regeneration capacity within the caudal fin, suggesting that blastema formation does not depend on a pool of stem/progenitor cells that require Wnt/ß-catenin signalling for their survival.
authors.affiliation: Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal.
authors.forename: Ana Sofia
authors.initials: AS
authors.lastname: Azevedo
authors.forename: Bartholomäus
authors.initials: B
authors.lastname: Grotek
authors.forename: António
authors.initials: A
authors.lastname: Jacinto
authors.forename: Gilbert
authors.initials: G
authors.lastname: Weidinger
authors.forename: Leonor
authors.initials: L
authors.lastname: Saúde
mesh_terms: D000671:Amputation, Surgical; D058500:Animal Fins / Q000196:embryology* / Q000502:physiology*; D000818:Animals; D005121:Extremities / Q000254:growth & development* / Q000601:surgery*; D007124:Immunoenzyme Techniques; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D012038:Regeneration / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism; D014945:Wound Healing; D015027:Zebrafish / Q000502:physiology*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin; C501128:dkk1b protein, zebrafish