Wnt signaling interacts with Shh to regulate taste papilla development

Ken Iwatsuki*, Hong Xiang Liu, Albert Gründer, Meredith A. Singer, Timothy F Lane, Rudolf Grosschedl, Charlotte M. Mistretta, Robert F. Margolskee

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

136 Scopus citations


Wnt and Shh signaling pathways are critical for the development and maturation of many epithelial tissues. Both pathways have roles in stem cell maintenance, tissue development, and tumorigenesis. However, linkage between these pathways in mammalian systems had not been well established. Here, we report that Shh expression in fungiform papillae and formation of normal mature fungiform papillae depend on signaling through Wnt and β-catenin. We observed that during fungiform papilla formation in mice, Shh and components of the Wnt/β-catenin signaling pathway are expressed together in the developing placode. The elimination of Wnt/β-catenin signaling in either Lef1 or Wnt 10b knockout mice resulted in down-regulation of Shh expression. In addition, the size and number of fungiform papillae were greatly reduced in Lef1 knockout mice. By examining embryonic mouse tongues in culture we determined that activation of Wnt/β-catenin signaling up-regulates Shh expression. We observed that blocking Shh signaling in cultured tongue explants enhanced papillae formation and was accompanied by an up-regulation of Wnt/β-catenin signaling, indicating that Shh inhibits the Wnt/β-catenin pathway. Exogenously added Shh suppressed expression of endogenous Shh and inhibited Wnt/β-catenin signaling (assessed in TOPGAL mice), further implicating Shh as an inhibitor of the Wnt/β-catenin pathway. Our observations indicate that Wnt/β-catenin signaling and interactions between the Wnt and Shh pathways play essential roles in the development of fungiform papillae.

Original languageEnglish (US)
Pages (from-to)2253-2258
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number7
StatePublished - Feb 13 2007


  • Fungiform papilla
  • Lef1
  • Wnt10b
  • β-catenin

ASJC Scopus subject areas

  • General


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