• Register
X
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

X

Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.

No
Yes

Early developmental specification of the thyroid gland depends on han-expressing surrounding tissue and on FGF signals.

The thyroid is an endocrine gland in all vertebrates that develops from the ventral floor of the anterior pharyngeal endoderm. Unravelling the molecular mechanisms of thyroid development helps to understand congenital hypothyroidism caused by the absence or reduction of this gland in newborn humans. Severely reduced or absent thyroid-specific developmental genes concomitant with the complete loss of the functional gland in the zebrafish hands off (han, hand2) mutant reveals the han gene as playing a novel, crucial role in thyroid development. han-expressing tissues surround the thyroid primordium throughout development. Fate mapping reveals that, even before the onset of thyroid-specific developmental gene expression, thyroid precursor cells are in close contact with han-expressing cardiac lateral plate mesoderm. Grafting experiments show that han is required in surrounding tissue, and not in a cell-autonomous manner, for thyroid development. Loss of han expression in the branchial arches and arch-associated cells after morpholino knock-down of upstream regulator genes does not impair thyroid development, indicating that other han-expressing structures, most probably cardiac mesoderm, are responsible for the thyroid defects in han mutants. The zebrafish ace (fgf8) mutant has similar thyroid defects as han mutants, and chemical suppression of fibroblast growth factor (FGF) signalling confirms that this pathway is required for thyroid development. FGF-soaked beads can restore thyroid development in han mutants, showing that FGFs act downstream of or in parallel to han. These data suggest that loss of FGF-expressing tissue in han mutants is responsible for the thyroid defects.

Pubmed ID: 17611226

Authors

  • Wendl T
  • Adzic D
  • Schoenebeck JJ
  • Scholpp S
  • Brand M
  • Yelon D
  • Rohr KB

Journal

Development (Cambridge, England)

Publication Data

August 11, 2007

Associated Grants

None

Mesh Terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors
  • Body Patterning
  • Branchial Region
  • Cell Differentiation
  • Embryo, Nonmammalian
  • Fibroblast Growth Factors
  • Gene Expression Regulation, Developmental
  • Mesoderm
  • Models, Biological
  • Signal Transduction
  • Stem Cells
  • Thyroid Gland
  • Tissue Distribution
  • Transplants
  • Zebrafish
  • Zebrafish Proteins