Islet is a key determinant of ascidian palp morphogenesis

Eileen Wagner, Alberto Stolfi, Yoon Gi Choi, Mike Levine

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The anterior-most ectoderm of ascidian larvae contains the adhesive papillae, or palps, which play an important role in triggering the metamorphosis of swimming tadpoles. In Ciona intestinalis, the palps consist of three conical protrusions within a field of thickened epithelium that form late in embryogenesis, as tailbuds mature into larvae. The palp protrusions express the LIM-homeodomain transcription factor Islet. Protrusion occurs through differential cell elongation, probably mediated by Islet, as we find that ectopic expression of Islet is sufficient to promote cell lengthening. FGF signaling is required for both Islete xpression and palp morphogenesis. Importantly, we show that Islet expression can rescue the palpdeficient phenotype that results from inhibition of FGF signaling. We conclude that Isletis a key regulatory factor governing morphogenesis of the palps. It is conceivable that Isletis also essential for the cellular morphogenesis of placode-derived sensory neurons in vertebrates.

Original languageEnglish (US)
Pages (from-to)3084-3092
Number of pages9
JournalDevelopment (Cambridge)
Issue number15
StatePublished - Aug 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Developmental Biology


  • Ascidian
  • Cell shape
  • Islet
  • LIM domain
  • Palps
  • Placode


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