Divergent requirements for fibroblast growth factor signaling in zebrafish maxillary barbel and caudal fin regeneration

Duszynski, R.J., Topczewski, J., and LeClair, E.E.
Development, growth & differentiation   55(2): 282-300 (Journal)
Registered Authors
Duszynski, Rob, LeClair, Elizabeth E., Topczewski, Jacek
fibroblast growth factor 20a protein, Fgf41, heat-shock proteins, hsp70l, singal transduction, wound healing
MeSH Terms
  • Amputation
  • Animal Fins/metabolism
  • Animal Fins/physiology*
  • Animal Fins/surgery
  • Animal Structures/metabolism
  • Animal Structures/physiology*
  • Animal Structures/surgery
  • Animals
  • Animals, Genetically Modified
  • Female
  • Fibroblast Growth Factors/genetics
  • Fibroblast Growth Factors/physiology*
  • Gene Expression Regulation, Developmental
  • Green Fluorescent Proteins/genetics
  • Green Fluorescent Proteins/metabolism
  • Male
  • Microscopy, Fluorescence
  • Mutation
  • Receptor, Fibroblast Growth Factor, Type 1/genetics
  • Receptor, Fibroblast Growth Factor, Type 1/metabolism
  • Receptor, Fibroblast Growth Factor, Type 1/physiology
  • Receptors, Fibroblast Growth Factor/genetics
  • Receptors, Fibroblast Growth Factor/metabolism
  • Receptors, Fibroblast Growth Factor/physiology*
  • Regeneration/genetics
  • Regeneration/physiology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction/genetics
  • Signal Transduction/physiology
  • Temperature
  • Zebrafish/genetics
  • Zebrafish/growth & development
  • Zebrafish/physiology
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/physiology*
23350700 Full text @ Dev. Growth Diff.

The zebrafish maxillary barbel is an integumentary organ containing skin, glands, pigment cells, taste buds, nerves, and endothelial vessels. The maxillary barbel can regenerate (LeClair & Topczewski 2010); however, little is known about its molecular regulation. We have studied fibroblast growth factor (FGF) pathway molecules during barbel regeneration, comparing this system to a well-known regenerating appendage, the zebrafish caudal fin. Multiple FGF ligands (fgf20a, fgf24), receptors (fgfr1-4) and downstream targets (pea3, il17d) are expressed in normal and regenerating barbel tissue, confirming FGF activation. To test if specific FGF pathways were required for barbel regeneration, we performed simultaneous barbel and caudal fin amputations in two temperature-dependent zebrafish lines. Zebrafish homozygous for a point mutation in fgf20a, a factor essential for caudal fin blastema formation, regrew maxillary barbels normally, indicating that the requirement for this ligand is appendage-specific. Global overexpression of a dominant negative FGF receptor, Tg(hsp70l:dn-fgfr1:EGFP)pd1 completely blocked fin outgrowth but only partially inhibited barbel outgrowth, suggesting reduced requirements for FGFs in barbel tissue. Maxillary barbels expressing dn-fgfr1 regenerated peripheral nerves, dermal connective tissue, endothelial tubes, and a glandular epithelium; in contrast to a recent report in which dn-fgfr1 overexpression blocks pharyngeal taste bud formation in zebrafish larvae (Kapsimali et al. 2011), we observed robust formation of calretinin-positive tastebuds. These are the first experiments to explore the molecular mechanisms of maxillary barbel regeneration. Our results suggest heterogeneous requirements for FGF signaling in the regeneration of different zebrafish appendages (caudal fin versus maxillary barbel) and taste buds of different embryonic origin (pharyngeal endoderm versus barbel ectoderm).

Genes / Markers
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Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes